Weapon System Sustainment: Selected Air Force and Navy Aircraft Generally Have Not Met Availability Goals, and DOD and Navy Guidance Need to Be Clarified

DOD spends billions of dollars annually to sustain its weapon systems to support current and future operations. The Air Force and Navy are operating many of their fixed-wing aircraft well beyond their original designed service lives and therefore are confronted with sustainment challenges.

House Report 114-537 included a provision for GAO to evaluate the sustainment of major weapon systems. This report, among other things, (1) examines the trends in availability and O&S costs for selected Air Force and Navy fixed-wing aircraft since fiscal year 2011, including whether they met availability goals, and (2) assesses the extent that the departments documented sustainment strategies, reviewed sustainment metrics, and implemented plans to improve aircraft availability. GAO selected a nongeneralizable sample of 12 fixed-wing aircraft by considering a variety of factors, such as the type, age, and manufacturer of the aircraft, among other factors, and analyzed condition and availability data, O&S costs, and sustainment challenges from fiscal year 2011 through March 2017 for each aircraft in a “Sustainment Quick Look.” GAO also analyzed policies, strategies, and plans, and interviewed Navy and Air Force officials in program offices, squadrons, and maintenance depots.

Between fiscal years 2011 and 2016, the Air Force and Navy generally did not meet aircraft availability goals, and operating and support (O&S) cost trends for GAO's selected fixed-wing aircraft varied. Specifically, GAO found that

availability declined for 6 of 12 aircraft—3 from each service—between fiscal years 2011 and 2016;

availability fell short of goals for 9 of 12 aircraft in fiscal year 2016; and

O&S costs increased for 5 of the aircraft, and maintenance costs—the largest share—increased for 8 of 12 aircraft.

GAO found, and officials agreed, that these aircraft face similar challenges.

a Obsolescence means a part is unavailable due to its lack of usefulness or it is no longer current or available for production.

b Diminishing manufacturing sources is a loss or impending loss of manufacturers or suppliers.

The Air Force and Navy have documented sustainment strategies for some aircraft, regularly reviewed sustainment metrics, and implemented improvement plans. The Air Force has documented sustainment strategies for all aircraft GAO reviewed; however, the Navy has not documented or updated its sustainment strategies for four aircraft. Specifically, the Navy does not have a documented sustainment strategy for the C-2A, and has not updated the strategies for the E2C, EA-18G, and F/A-18A-D since before 2012. The Navy is in the process of documenting its strategies, but Department of Defense (DOD) policy is unclear on whether a sustainment strategy is required and has to be updated every 5 years for weapon systems that are in the operations and support phase of their life cycle (i.e., legacy systems). Also, Navy guidance does not specify a requirement for legacy systems, although Air Force guidance does. Clarifying the requirements to document sustainment strategies for legacy systems, and documenting those strategies, would add additional visibility over the availability and O&S costs of DOD aircraft and any associated sustainment risks.

This is a public version of a sensitive report issued in April 2018. Information on aircraft availability and other related information was deemed to be sensitive and has been omitted from this report.

GAO is recommending that DOD and the Navy update or issue new policy and guidance clarifying the requirements for documenting sustainment strategies for legacy weapon systems. DOD concurred with the recommendations.

The Department of Defense (DOD) spends tens of billions of dollars  annually to sustain its weapon systems in an effort to ensure that these  systems are available to simultaneously support today’s military  operations and maintain the capability to meet future defense  requirements. Operating and support (O&S) costs historically account for  approximately 70 percent of a weapon system’s total life-cycle cost— costs to operate and sustain the weapon system from initial operations  through the end of its life—and include costs for repair parts, depot and  field maintenance, contract services, engineering support, and personnel,  among other things. Weapon systems are costly to sustain in part  because they often incorporate a complex array of technical subsystems  and components and need expensive repair parts and logistics support to  meet required readiness levels. In addition, as we reported in 2014,   military operations have increased the wear and tear on many weapon  systems, including fixed-wing aircraft, and escalated their O&S costs  beyond peacetime levels.

The Departments of the Air Force and Navy are operating many of their  fixed-wing aircraft well beyond their original designed service lives, and  some of these legacy systems are confronted with sustainment  challenges that affect aircraft availability. The Air Force and Navy  forecast needed aircraft availability and associated goals to ensure that  fixed-wing aircraft can meet operational and training requirements. In  2017, senior Air Force, Navy, and Marine Corps officials testified before  the House Armed Services Committee regarding, among other things, the  maintenance and sustainment issues relating to aging aircraft that are  affecting the readiness of their forces. Additionally, over the past several  years, we have conducted work on a number of issues that affect the  ability of DOD to sustain its weapon systems, an overview of which can  be found in appendix I.

We conduct annual assessments of DOD’s major defense acquisition  programs and report on the cost, schedule, and performance of those  programs. To complement our acquisition-related work on major weapon  systems, the House Armed Services Committee in House Report 114-537  accompanying a bill for the National Defense Authorization Act for Fiscal  Year 2017 included a provision for us to evaluate the sustainment,  availability, and costs of major weapon systems, among other things.  This report (1) examines trends in aircraft availability and O&S costs for  selected Air Force and Navy fixed-wing aircraft since fiscal year 2011,  including whether the aircraft met availability goals; (2) describes the  sustainment challenges that affect aircraft availability and O&S costs  across the selected fixed-wing aircraft; and (3) assesses the extent that  the Air Force and Navy have documented sustainment strategies,  reviewed sustainment metrics, and implemented plans to improve aircraft  availability for the selected fixed-wing aircraft. Additionally, in appendixes  II–XIII we provide “Sustainment Quick Looks” for each of the fixed-wing  aircraft we reviewed. These “Sustainment Quick Looks” include additional  information for each of the fixed wing aircraft we reviewed.

This report is a public version of a sensitive report that we issued on April  25, 2018. The sensitive report included an objective related to the trends  in aircraft availability. DOD deemed some of the information, such as  aircraft availability, not mission capable status, number of aircraft in  depots, and budgeted and executed flight hours, to be sensitive (i.e., For  Official Use Only), which must be protected from public disclosure. This  public report omits the information that DOD deemed to be sensitive.  Although the information provided in this report is more limited, it  addresses the same objectives and uses the same methodology as the  sensitive report.

For objective one, we selected a nongeneralizable sample of 12 types of  fixed-wing aircraft managed by the Air Force and Navy and reviewed  aircraft availability and other sustainment data calculated based on the  number of aircraft and period of time and O&S costs from fiscal years  2011 through 2016, the last fiscal year for which complete data were  available at the time of our work. We selected this period so we could  identify and obtain insight on historical data trends regarding aircraft  availability and O&S costs for the selected fixed-wing aircraft. We  compared the availability data over this period to Air Force and Navy availability goals associated with each aircraft fleet. To select the fixed- wing aircraft for our review, we considered a number of factors, such as  the type of aircraft (fighters, bombers, cargo, etc.), the size and age of the  inventory, and whether the aircraft were sustained organically by DOD or  through contract arrangements, such as public-private partnerships or  performance-based logistics contracts. For the Air Force, we selected  five fixed-wing aircraft—the B-52 Stratofortress, C-17 Globemaster III, F- 16 Fighting Falcon, F-22 Raptor, and E-8C Joint Surveillance and Target  Attack Radar System (JSTARS). For the Navy, including the Marine  Corps, we selected seven fixed-wing aircraft: the AV-8B Harrier, C-2A  Greyhound Logistics Aircraft, E-2C Hawkeye Early Warning and Control  Aircraft, E-2D Advanced Hawkeye Early Warning and Control Aircraft,  EA-18G Growler, F/A-18A-D Hornet Strike Fighter, and F/A-18E-F Super  Hornet. For the selected aircraft, we obtained and reviewed the aircraft  availability, sustainment, and O&S data for accuracy and completeness,  interviewed officials regarding their data-collection processes, and  reviewed available related policies and procedures associated with the  collection of the data. We found the information to be sufficiently reliable  for the purposes of presenting sustainment metrics, such as aircraft  availability and O&S costs.

For objective two, we reviewed sustainment metrics, performance  briefings, and other relevant documentation to identify specific challenges  for each of the 12 aircraft in our review. We also reviewed ongoing and  planned actions to address those challenges. We interviewed program  officials, depot officials, field maintainers, and squadrons to obtain their  views on the challenges they face in sustaining the aircraft and the  actions they take to mitigate those challenges. In some instances, we  visited depots and squadrons to observe aircraft undergoing  maintenance, discuss the respective maintenance processes, and  discuss challenges and mitigation actions with officials.

For objective three, we obtained and analyzed the sustainment strategies,  performance management frameworks (i.e., sustainment metrics  collected and monitored as well as the levels of management review), and improvement plans for each of the 12 selected fixed-wing aircraft. We  also identified and reviewed DOD, Air Force, and Navy guidance to  analyze the departments’ efforts in sustaining these aircraft. Specifically,  we reviewed the Air Force and Navy guidance to determine whether it  was consistent with DOD policy and federal standards for internal control  that deal with management defining objectives in specific terms.  Additionally, we identified whether the Air Force and Navy had  documented sustainment strategies for each selected fixed-wing aircraft,  including a life-cycle sustainment plan, postproduction support plan, or an  in-service support plan, among other types of documented strategies.  Further, we determined whether the sustainment strategy for each  selected fixed-wing aircraft had been updated within time frames  identified in DOD policy. Appendix XIV provides further information on our  scope and methodology.

The performance audit upon which this report is based was conducted  from September 2016 to April 2018 in accordance with generally  accepted government auditing standards. Those standards require that  we plan and perform the audit to obtain sufficient, appropriate, evidence  to provide a reasonable basis for our findings and conclusions based on  our audit objectives. We believe that the evidence obtained provides a  reasonable basis for our findings and conclusions based on our audit  objectives. We subsequently worked with DOD from April 2018 to  September 2018 to prepare this unclassified version of the original  sensitive report for public release. This public version was also prepared  in accordance with these standards.

Information on Selected Air Force and Navy Fixed- Wing Aircraft

The inventories of the selected Air Force and Navy fixed-wing aircraft in  our review totaled 2,823 aircraft and required approximately $20 billion to  operate and support in fiscal year 2016. The inventory, aircraft status,  initial operational capability, and service life forecast for each of the 12  selected fixed-wing aircraft are shown in figure 1.

Policy and Guidance for the Sustainment of Fixed- Wing Aircraft

Sustainment of fixed-wing aircraft and other weapon systems comprises  the logistics and personnel services required to maintain and prolong  operations, and DOD policy provides direction to service components on  sustainment planning across the life cycle of the weapon system.  Specifically, DOD policy requires the services to develop and implement a  sustainment strategy, such as a Life-cycle Sustainment Plan, for  sustaining its weapon systems. According to DOD’s policy, this strategy  should be the basis for all sustainment efforts, including sustainment  metrics mapped to key performance parameters and key system  attributes, such as aircraft availability, to manage sustainment  performance. The policy states that, after initial operating capability,  programs should update the sustainment plan whenever there are major  changes to its strategy for sustaining the weapon system, or every 5  years, whichever occurs first. The Air Force and the Navy also have  guidance that implements the requirements of the DOD guidance.  These services’ guidance include sustainment-planning requirements for  life-cycle sustainment and assurance of affordability.

Roles and Responsibilities for the Sustainment of Fixed-Wing Aircraft

There are a variety of DOD offices that have roles and responsibilities  related to sustaining fixed-wing aircraft. For instance, the Under Secretary  of Defense for Acquisition and Sustainment (USD ), is the principal  staff assistant and advisor to the Secretary of Defense for all matters  concerning acquisition and sustainment. Specifically, USD (A&S) is  responsible for establishing policies for logistics, maintenance, and  sustainment support for all elements of DOD, including fixed-wing aircraft.  The Assistant Secretary of Defense for Logistics and Materiel Readiness  (ASD ) serves as the principal staff assistant and advisor to the  USD (A&S) on logistics and materiel readiness within DOD. Specifically,  the ASD (L&MR) is responsible for (1) establishing DOD policies and  procedures for logistics, maintenance, materiel readiness, strategic  mobility, and sustainment support; (2) providing related guidance to the  Secretaries of the military departments, including developing the Life- cycle Sustainment Plan outline; and (3) monitoring and reviewing  programs associated with these areas, among other duties and  responsibilities.

For the Air Force, the Air Force Materiel Command develops, acquires,  and sustains weapon systems through research, development, testing,  evaluation, acquisition, maintenance, and program management of the  systems and their components. This command provides acquisition and  life-cycle management services and logistics support, among other  things. The Air Force Life Cycle Management Center within the Air Force  Materiel Command is responsible for the life-cycle management of  weapon systems from inception to retirement. A Program Executive  Officer—responsible for managing a specific portfolio of weapon  systems—is responsible for each of the selected fixed-wing aircraft. The  Program Executive Officer oversees the program office that manages  each weapon system.

For the Navy and Marine Corps, the Naval Air Systems Command is  responsible for providing the full life-cycle support of naval aviation  aircraft, weapons, and systems. This support includes research, design,  development and systems engineering; acquisition; test and evaluation;  training facilities and equipment; repair and modification; and in-service  engineering and logistics support. As with the Air Force, Program  Executive Officers oversee their assigned program managers.

DOD relies on program managers to lead the development, delivery, and  sustainment of individual weapon systems through their life cycles. The  program managers are the designated individuals with responsibility for  and authority to accomplish the program’s sustainment objectives to meet  the users’ operational needs. Product support managers, who work within  the program offices, are responsible for developing and implementing  support strategies for weapon systems that maintain readiness and  control life-cycle costs. Weapon systems are sustained under various  arrangements that may include contractors, DOD organic facilities, or  some combination of the two. For example, the Air Force Sustainment  Center provides depot maintenance through its Air Logistics Complexes  for weapon systems. Naval Air Systems Command is responsible for  the Navy Fleet Readiness Centers, which provide depot-level  maintenance for Navy and Marine Corps fixed-wing aircraft.  Additionally, the Air Force Sustainment Center and the Navy Supply  Systems Command, as well as the Defense Logistics Agency, manage  inventories of repair parts, and individual weapon systems programs are  typically supported by a complex supplier network that includes a prime  contractor, subcontractors, and various tiers of parts suppliers. On the  other hand, sustainment responsibilities—in their entirety or particular  elements—may be contracted out as part of a public-private partnership  or a performance-based logistics agreement, such as with the F-22  Raptor.

Key Sustainment Metrics for Fixed-Wing Aircraft

The Air Force and Navy monitor the readiness status of selected fixed- wing aircraft through numerous performance metrics. Specifically, the Air  Force measures how well a fleet is performing by calculating the  availability of the fleets’ aircraft, which is the number of aircraft that are  available for flight operations. The Navy measures its aircraft availability  through two metrics: (1) Ready-Basic-Aircraft (RBA)—the number of  aircraft that are able to safely fly—and (2) Ready-for-Tasking (RFT)—the  number of aircraft that are able to conduct specific missions. Both the Air  Force and Navy have established goals associated with aircraft  availability.

In addition to measuring the availability of the aircraft against the  associated goals, the Air Force and Navy track the reasons for aircraft not  being available or able to conduct missions. Specifically, the Air Force  and Navy track the following:

Aircraft in depot: Aircraft unavailable to conduct missions because of  scheduled or unscheduled depot maintenance or modification.

Not mission capable maintenance: Aircraft that are not in depot and  not capable of performing any of their assigned missions because of  maintenance.

Not mission capable supply: Aircraft that are not in depot and not  capable of performing any of their assigned missions because of the  lack of a repair part.

In addition to these three metrics, the Air Force also tracks the following:

Not mission capable for both supply and maintenance: Aircraft  that are not in depot and not capable of performing any of their  assigned missions because of both maintenance and the lack of a  repair part.

Units possessed not reported: Aircraft that are not available for use  for reasons other than depot and not mission capable status, but  possessed by the squadron.

Operating and Support Costs for Major Weapon Systems

There are various costs associated with operating and supporting weapon  systems. DOD’s Operating and Support Cost-Estimating Guide provides  direction to the service components on developing estimates to support  various analyses and reviews throughout the program life cycle.  According to the guide, as a program matures, it remains necessary to  continue to track and assess O&S costs and trends to ensure that the  program remains sustainable, affordable, and properly funded. Each  military department maintains a database that collects historical data on  the O&S costs for major fielded weapon systems. DOD’s Office of Cost  Assessment and Program Evaluation provides policy guidance on this  requirement, known as the Visibility and Management of Operating and  Support Costs program; specifies the common format in which the data  are to be reported; and monitors its implementation by each of the military  departments. O&S costs are categorized using the following six  overarching elements: unit level manpower—cost of operators, maintainers, and other  support manpower assigned to operating units; unit operations—cost of unit operating materiel such as fuel, and  training material, unit support services, and unit travel; maintenance—cost of system maintenance including depot- and  sustaining support—cost of system support activities that are provided  by organizations other than the system’s operating units;  continuing system improvements—cost of system hardware and  software modifications; and  indirect support—cost of activities that provide general services that  lack the visibility of actual support to specific force units or systems.

Air Force and Navy Fixed-Wing Aircraft Availability and O&S Costs Have Varied, and Aircraft Availability Goals Generally Were Not Met

For the selected Air Force and Navy fixed-wing aircraft in our review,  aircraft availability and O&S cost trends varied over the 6-year period  between fiscal years 2011 and 2016, and the aircraft generally did not  meet availability goals. We found that 6 of 12 fixed-wing aircraft—3 from  each service—experienced decreased aircraft availability between fiscal  years 2011 and 2016. One aircraft met availability goals each year  between fiscal year 2011 and 2016. Conversely, six aircraft met the goals  in some years but not others, and five aircraft did not meet the goals in  any year. In the latest year included in our review—fiscal year 2016—9 of  12 of the fixed-wing aircraft did not meet their associated availability  goals. With respect to O&S costs, the overall O&S total for all 12 aircraft  was about $20 billion annually over the 6-year period; some aircraft  experienced increases while the costs to operate and support others  decreased. The reasons for changes in costs included increases in  maintenance costs for 8 of 12 fixed-wing aircraft. Below we summarize  these trends, and the “Sustainment Quick Looks” in appendices II–XIII  provide detailed information on the trends associated with each of the 12  fixed-wing aircraft and appendix XV provides additional information on  operating and support cost per aircraft.

Air Force Aircraft Availability and O&S Cost Trends Varied across the Selected Fixed-Wing Aircraft

Air Force Aircraft Availability Trends Varied, and Three of Five Aircraft Did Not Meet Availability Goals since 2011

Our analysis found that: between fiscal years 2011 and 2016, aircraft availability for two of five  selected Air Force fixed-wing aircraft fluctuated and for three  decreased; between fiscal 2011 and 2016, two aircraft met availability goals in  some years, and three aircraft did not meet availability goals in any of  the years; and  in fiscal year 2016, four of the five aircraft did not meet availability  goals.

Specific details regarding aircraft availability and not mission capable  status for maintenance, supply, and both maintenance and supply were  omitted because DOD deemed this information as sensitive (i.e., For  Official Use Only).

According to officials, when aircraft availability goals are not met, training  and operational missions may not be fulfilled as timely as needed. For  example, F-22 squadron officials explained that the lack of available  aircraft creates a shortage of trained pilots. F-22 pilots need extensive  training to fulfill their air-superiority role. Further, command officials  explained that when aircraft availability goals are not met, there may not  be enough aircraft to respond to contingency requirements. Officials  expressed concern that, given the capability and expectation of the F-22  to be available to create air superiority in any operation, missions may not  be met. Additionally, E-8C program office officials stated that missions are  often limited to top priority, which means supported combatant commands  may not obtain all needed capabilities, such as the E-8C not being able to  provide surveillance capability to particular combatant commands.

Air Force O&S Cost Trends Have Varied, and Maintenance Costs Generally Increased since 2011

From fiscal years 2011 through 2016, O&S costs for the Air Force aircraft  in our review totaled about $13 billion annually. These costs decreased  for the C-17, F-16, and the F-22, but increased for the B-52 and E-8C, as  shown in figure 2. For example, the F-16’s total annual O&S costs  decreased by about $943 million (or about 19 percent) because of  decreases in all cost elements—the largest decrease being unit  operations—except sustaining support. According to officials, the  decrease in unit operations can be attributed to the retiring of aircraft and  the consolidation of squadrons. The C-17’s and F-22’s O&S costs  decreased mainly because of decreases in two cost elements: continuing  system improvements and unit operations. In contrast, the B-52’s and the  E-8C’s O&S costs increased, by $76 million (or about 6 percent) and $41  million (or about 6 percent), respectively. The increases occurred  because two of the cost elements—continuing system improvements and  maintenance costs—increased more than the other costs elements  decreased.

Based on our analysis of the O&S cost elements, maintenance cost  generally is one of the largest portions—on average about 36 percent—of  total O&S costs for each aircraft. As shown in figure 3, maintenance costs  for four of the five aircraft generally have increased from fiscal years 2011  through 2016. Specifically, maintenance costs for the C-17, E-8C, and F- 22 increased because of additional depot maintenance needs. B-52  maintenance costs fluctuated year to year, but increased overall during  this period. The overall maintenance costs for the F-16 decreased by  approximately $140 million. According to our analysis, even though there  was an increase in some of the F-16 maintenance cost elements, the  fleet’s executed flying hours decreased. Therefore, the flying hour depot- level reparable costs decreased by approximately $123 million and  engine repair decreased by $115 million, causing the overall maintenance  cost to decrease.

Navy Aircraft Availability Trends and O&S Cost Trends Varied across the Selected Fixed-Wing Aircraft

Navy Aircraft Availability Trends Varied, and Five of Seven Aircraft Generally Did Not Meet Availability Goals since 2011

Our analysis found that: between fiscal years 2011 and 2016, aircraft availability increased for  three of the seven Navy fixed-wing aircraft, fluctuated for one, and  decreased for the remaining three aircraft; between fiscal 2011 and 2016, one aircraft met aircraft availability  goals in each year, and four aircraft met goals in some years, while  two aircraft did not meet goals in any of the years; and  in fiscal year 2016, the Navy did not meet aircraft availability goals for  five of the seven aircraft.

Specific details regarding aircraft availability and not mission capable  status for maintenance and supply were omitted because DOD deemed  this information as sensitive (i.e., For Official Use Only).

To address decreases in aircraft availability, the Navy has moved  available aircraft between squadrons to help ensure deploying squadrons  are fully equipped for their assigned missions. In November 2017, the  Commander of Naval Air Forces testified before the House Armed  Services Committee that to equip the air wings with the required number  of mission capable aircraft for the deployment of three aircraft carriers in  2017, the Navy had to transfer 94 strike fighters to and from the  maintenance depots or between squadrons. This transfer included  pulling aircraft from fleet replacement squadrons, where the focus should  be on training new aviators.

The Commander of Naval Air Forces, in his November 2017 testimony,  summarized the issue: “That strike fighter inventory management, or shell  game, leaves non-deployed squadrons well below the number of jets  required to keep aviators proficient and progressing toward their career  qualifications and milestones, with detrimental impacts to both retention  and future experience levels.” Furthermore, based on our analysis, F/A- 18A-D squadrons have underexecuted their flight hours by an average of  4 percent from fiscal years 2011 through 2016. According to officials, this  is largely due to low aircraft availability. Additionally, placing further strain  on aircraft availability, the F/A-18A-D inventory has decreased from 581  aircraft in fiscal year 2011 to 537 aircraft in fiscal year 2016.

The Navy’s O&S and Maintenance Cost Trends Varied

From fiscal years 2011 through 2016, O&S costs for the Navy’s seven  selected fixed-wing aircraft totaled about $7 billion annually. Also, the  Navy has experienced varying O&S and maintenance costs since fiscal  year 2011 for these aircraft. Specifically, annual O&S costs decreased for  the AV-8B, C-2A, E-2C, and F/A-18A-D, and increased for the E-2D, EA- 18G, and F/A-18E-F, as shown in figure 4.

We found that O&S costs for the F/A-18A-D decreased by about 22  percent from about $3.1 billion in fiscal year 2011 to about $2.4 billion in  fiscal year 2016. According to officials, this decrease can be attributed to  the decrease in inventory as aircraft are retired and squadrons transition  to the F-35 Joint Strike Fighter. In another example, O&S costs for the E- 2D increased from about $1.6 million in fiscal year 2012 to about $125  million in fiscal year 2016. The size of the fleet has increased by 17  aircraft—from 3 to 20 since fiscal year 2011. According to officials, this  aircraft remains in production with a projected fleet size of 75; as  inventory increases, so will O&S costs.

Based on our analysis of the O&S cost elements, maintenance cost  generally is one of the largest portions—about 42 percent—of total O&S  costs for the seven aircraft in our review. Annual maintenance costs have  increased for the C-2A, E-2D, EA-18G, and F/A-18E-F, and decreased for  the AV-8B, E-2C, and F/A-18A-D, as shown in figure 5.

We found that maintenance cost for the C-2A increased by about 7  percent from about $89 million in fiscal year 2011 to about $95 million in  fiscal year 2016. According to officials, the increase in maintenance cost  can be attributed to increased demand for outer wing panels, which  resulted in a $16 million increase in depot-level repair costs and a more  than 10 percent increase in executed flight hours, among other things. In  another example, maintenance cost for the AV-8B decreased by about 9  percent from about $375 million in fiscal year 2011 to about $341 million  in fiscal year 2016. According to officials, these decreases can be  attributed to the AV-8B no longer being used in Operation Enduring  Freedom in 2012, the loss of six aircraft, and the transition of AV-8B  squadrons to the F-35 Joint Strike Fighter.

The Air Force and Navy Face Similar Sustainment Challenges That Affect Aircraft Availability and O&S Costs across the Selected Fixed-Wing Aircraft

The Air Force and Navy face similar sustainment challenges that relate to  aging, maintenance, and supply support that affect aircraft availability and  O&S costs for the 12 aircraft selected in our review, as shown in figure 6.

Specifically, 10 of 12 aircraft are experiencing sustainment challenges  related to aging; all 12 are experiencing challenges related to  maintenance; and all 12 are also experiencing challenges related to  supply support. Below is a brief overview of these challenges:

Aging: A number of these aircraft are aging and operating beyond  their planned service life, partly because of delays in replacement  aircraft. Specifically, the Air Force and Navy plan to replace the F-16,  AV-8B, and F/A-18A-D with the F-35 Joint Strike Fighter. The Navy is  expected to transition the F/A-18A-D through 2030 and the Marine  Corps is planning to use the F/A-18A-D beyond 2030 (although these  time frames have been extended several times already). The Navy  plans to retire the AV-8B in 2026. On the other hand, the Air Force is  not expected to retire the F-16 until at least 2040. Because of aging,  according to officials, there are parts on some aircraft that need to be  repaired and replaced that were not accounted for during initial  sustainment analysis. To mitigate some challenges associated with  the age of the fixed-wing aircraft, the Air Force and Navy program  officials have decided to extend the service life of some aircraft by  repairing and overhauling airframes and components, as well as  developing the engineering specifications for parts that were never  planned to be repaired or replaced.

Maintenance: Delays in getting aircraft into and through depot  maintenance, as well as shortages of skilled maintainers, are  contributing to some aircraft missing their availability goals. Both  services reported losing experienced maintainers, either to retirement  or to other programs such as the F-35 Joint Strike Fighter. To address  maintenance challenges, program offices for the selected aircraft  have improved the efficiency and speed of depot maintenance, as  well as are working to ensure there are sufficient numbers of trained  maintainers.

Supply Support: Some aircraft are encountering supply shortages as  a result of parts not being available, in some cases due to  obsolescence issues or diminishing manufacturer sources.  Overcoming part shortages through either searching for replacement  parts or reengineering parts takes time, which can contribute to  aircraft being unavailable for longer periods. To mitigate supply  challenges, officials have proactively upgraded aircraft before  obsolescence occurs or located available parts and reengineered  parts that are no longer in production, as well as identified suitable  manufacturers in advance, among other things.

For more specific information on sustainment challenges related to aging  aircraft, maintenance, and supply support for each of the fixed-wing  aircraft, see the “Sustainment Quick Looks” in appendixes II–XIII.

Sustainment Strategies Were Documented for Some but Not All Aircraft, and the Air Force and Navy Have Other Efforts to Review and Improve Aircraft Availability

The Air Force has documented sustainment strategies for its five selected  aircraft in our review, but the Navy has not documented sustainment  strategies or updated the strategies for four of seven of its aircraft in our  review. The Air Force and Navy also regularly reviewed sustainment  metrics and have implemented plans to improve aircraft availability.

The Air Force Has Documented Sustainment Strategies, but Some of the Navy’s Strategies Are Not Documented or Up-to- Date

The Air Force has documented sustainment strategies for the five  selected fixed-wing aircraft and updated them in accordance with Air  Force guidance. However, the Navy has not documented a sustainment  strategy or updated the strategies for four of the seven aircraft in our  review since 2012. See figure 7 for the year of the most recent update to  the sustainment strategy for the aircraft in our review.

While sustainment strategies do not guarantee successful outcomes, they  serve as a tool to guide operations as well as support planning and  implementation of activities through the life-cycle of the aircraft.  Specifically, at a high-level the strategy is aimed at integrating  requirements, product support elements, funding, and risk management  to provide oversight of the aircraft. For example, these sustainment  strategies can be documented in a life-cycle sustainment plan,  postproduction support plan, or an in-service support plan, among other  types of documented strategies. Additionally, program officials stated that  an aircraft’s sustainment strategy is an important management tool for the  sustainment of the aircraft by documenting requirements that are known  by all stakeholders, including good practices identified in sustaining each  aircraft. For example:

The strategy for the Air Force B-52 has been updated several times in  recent years because of several major modifications. For example, in  2014 the Air Force issued an updated sustainment plan within the life- cycle management plan to update the combat network  communications technology program because the B-52’s  communications system is still the original from the 1950s and has  limitations related to making mission or target changes in flight. The  plan addresses the testing, resource management, and numerous  program performance indicators and requirements of the system.

The strategy for the Air Force F-16 outlines plans for the aircraft’s  service life extension and includes proactive measures and data  forecasting to bundle depot modifications in order to minimize fleet- wide effects on aircraft availability. The service life extension for the F- 16 is designed to extend the service life of 300 F-16 aircraft from  8,000 to 13,856 flight hours at an estimated cost of $740 million (as of  June 2016).

The strategy for the Navy E-2D provides a systematic approach to  ensure that a comprehensive support package is in place to support  the sustainment of the aircraft. Also, it describes the overall plan for  the management and execution of the product support package by  communicating the sustainment strategy to stakeholders in the  acquisition, engineering, and logistics communities.

However, the Navy had not documented a sustainment strategy for the C- 2A because a strategy was not required when the aircraft, now a legacy  system, was going through the acquisition process prior to 1965.  According to Navy officials, while they have not documented a strategy  for the C-2A, they are undertaking efforts, such as updating technical  publications, performing maintenance analysis on the landing gear, and  evaluating depot tasks to decrease turnaround time, among other efforts,  to sustain the aircraft. However, a documented sustainment strategy for  the C-2A would help guide the planning and implementation of these  efforts, as well as serve as a management tool by documenting these  requirements that are known by all stakeholders.

In addition, the Navy’s sustainment strategies for the E-2C (2011), EA- 18G (2006), and F/A-18A-D (2001) were developed prior to 2012 and  thus have not been updated in over 5 years. With respect to the EA-18G,  Navy officials told us that the sustainment strategy should be updated in  accordance with DOD’s acquisition policy—DOD Instruction 5000.02— since the EA-18G is still in the acquisition process, as it continues to be  produced. For the E-2C and F/A-18A-D, Naval Air Systems Command  officials and program office officials told us that they were not required to  document sustainment strategies because these aircraft were legacy  systems at the time the requirement to develop and maintain a  sustainment strategy was implemented. Therefore, according to these  officials, the DOD requirements to document and update sustainment  strategies every 5 years in DOD Instruction 5000.02 were not applicable.

DOD Instruction 5000.02 requires weapon systems to have some form of  a sustainment strategy that is not older than 5 years; however, it is  unclear whether this policy is applicable to legacy weapon systems.  Specifically, the policy states that program managers for all programs are  responsible for developing and maintaining a sustainment strategy, such  as a Life-cycle Sustainment Plan, beginning at the risk-reduction decision  point (i.e., Milestone A of the acquisition process). However, based on  our discussions with Navy program officials for our selected aircraft and  our review of the policy, it is unclear whether the policy—as currently  written—is applicable to legacy systems that were no longer in production  and thus had completed the risk-reduction decision point (or Milestone A)  prior to the requirement to update a sustainment strategy every 5 years.  According to DOD officials, the intent of the policy is for all programs,  including legacy weapon systems, to develop and maintain a sustainment  strategy; however, the policy does not explicitly state that legacy systems  are expected to fulfill this requirement.

In May 2017, the Air Force updated its sustainment guidance to require  sustainment strategies for legacy systems and for those strategies to be  updated every 5 years. Air Force officials told us that they did this  because the DOD policy was unclear whether it was applicable to legacy  systems and it was a good practice to ensure the guidance was explicit  for all weapon systems to document and update a sustainment strategy.  This instruction explicitly states that the requirement to document a  sustainment strategy and update it every 5 years is applicable to all  weapon systems, including legacy systems that are in the O&S phase of  their life cycles. Additionally, the Air Force Instruction states that these  legacy systems are not required to retroactively meet requirements  identified for previous phases of the acquisition life-cycle, but should meet  the requirements needed for continued operations of the system.

However, the Navy has not made the requirement explicit for legacy  systems in its guidance. Specifically, Navy guidance does not explicitly  state that documenting a sustainment strategy and updating that strategy  every 5 years is a requirement for legacy systems. While Navy guidance  requires the development and use of sustainment metrics for legacy  systems and requires the Naval Air Systems Command be responsible  for aviation weapon systems in sustainment, the Navy does not address  any requirement for sustainment strategies for legacy systems.

The lack of clarity in DOD Instruction 5000.02 and the Navy guidance  regarding whether legacy systems are required to document a  sustainment strategy and update that strategy every 5 years has resulted  in confusion regarding sustainment planning requirements among Navy  program offices and could cause confusion with other weapon system  program offices across DOD. Standards for Internal Control in the Federal  Government state that management should define objectives in specific  terms so they are understood at all levels of the entity. The standards  also state that guidance should clearly define what is to be achieved, who  is to achieve it, how it will be achieved, and the time frames for  achievement. As indicated by the Air Force’s 2017 update to its  sustainment guidance, clarifying DOD and Navy guidance and the  applicability of sustainment strategy requirements to legacy systems  could be done through very small additions and clarifications to the  applicable guidance documents. Until DOD and the Navy update or issue  new guidance clarifying the requirements for documenting sustainment  strategies for legacy systems, weapon system program offices, such as  those for fixed-wing aircraft, as well as Naval Air Systems Command and DOD may not have full visibility of necessary requirements to achieve  program objectives or any related risks associated with the sustainment  of these weapon systems.

While the DOD policy and Navy guidance is unclear, Naval Air Systems  Command and Navy program offices for the four aircraft—C-2A, E-2C,  EA-18G, and F/A-18A-D—that either do not have a sustainment strategy  or have not updated the strategy within the last 5 years are taking actions  to document or update the sustainment strategies for these aircraft.  According to Naval Air Systems Command officials, once it was brought  to their attention that the intent of DOD Instruction 5000.02 was for legacy  systems to have an updated documented sustainment strategy, they  began to take action to develop or update the respective sustainment  strategies. Specifically, according to C-2A, E-2C, and E-2D program  officials, they are currently updating the E-2D strategy for its 5-year  update, which is due in fiscal year 2018, and it will include updates for the  C-2A and E-2C since the airframe for all three aircraft are very similar.  Also, program officials for the EA-18G and F/A-18A-D told us that they  are currently updating the strategies for these aircraft and are expected to  complete the process in fiscal year 2018. Given that the Navy is already  taking action to update its sustainment strategies and has established  timelines for these updates, we are not making any recommendations to  the Navy regarding updating the respective sustainment strategies.

The Air Force and Navy Regularly Reviewed Sustainment Metrics and Implemented Improvement Plans to Address Aircraft Availability

The Air Force and the Navy have (1) regularly reviewed sustainment  metrics for fixed-wing aircraft and (2) implemented improvement plans to  address aircraft availability.

The Air Force and Navy Have Conducted Regular Reviews of Sustainment Metrics

The Air Force and Navy have regularly monitored the condition of their  fixed-wing aircraft, which includes measuring aircraft availability against  planned goals as well as monitoring other sustainment metrics.  Specifically, the Air Force Materiel Command monitors aircraft availability  and other sustainment metrics through quarterly Weapon System  Enterprise Review (WSER) briefings. The program office in conjunction  with the Air Force Life Cycle Management Center generates the WSER,  which is briefed through Air Force Materiel Command and the Program  Executive Offices to the Air Force Chief of Staff. The WSER delivers  insight into the comprehensive health of a system by flagging gaps in  performance and identifying mitigating actions, which is used to conduct  crosscutting enterprise analysis and provide input into readiness reviews.  In addition to the WSER, the program offices manage their performance  through their Health of the Fleet briefs. These briefs—conducted monthly  or quarterly depending upon the aircraft—include readiness assessments  that provide insight on maintenance and management practices. The  assessment is delivered by the program’s maintenance group, and  includes aircraft performance metrics, issues, actions, and schedules to  inform program leadership on fleet status and to help prioritize and make  decisions concerning the issues.

The Navy monitors aircraft availability through its aircraft status  dashboard for each aircraft, which provides specific information, such as  goals, actual availability, and gaps between the two. More specifically, the  Navy tracks the status of each of its aircraft through the dashboard,  including those aircraft that are available (i.e., Ready-Basic-Aircraft  ), are in depot maintenance, or are not mission capable due to  maintenance or supply, among other metrics. The dashboard is updated  monthly, and there are weekly meetings with key stakeholders, including  Naval Air Systems Command officials, industry partners, and depot  officials, to monitor the performance of each aircraft and make  adjustments to improve aircraft availability. Additionally, all program  offices have processes in place to manage the fleet within their portfolios,  including semiannual or annual program reviews such as Program  Management Reviews and Executive Steering Reviews. These reviews  focus on readiness, cost drivers, and initiatives to address program risk  and ways to resolve issues affecting each aircraft. Further, the Marine  Corps Commandant for Aviation leads biannual Executive Steering  Summits to assess readiness issues affecting Marine Corps aircraft.

The Air Force and Navy Have Implemented Improvement Plans to Address Aircraft Availability

The Air Force and Navy have implemented improvement plans to address  aircraft availability for each of the selected fixed-wing aircraft. Air Force  program offices for the fixed-wing aircraft in our review have plans for  improving availability. Since 2005, the Air Force Materiel Command has  had an annual process to improve aircraft availability, which is known as  the Aircraft Availability Improvement Program. The process enables the  program offices to assess and limit risk, incorporate available support  funding, and specifically address where there are effects on availability,  such as aircraft in depot. This process also incorporates projecting  historical and goal rates in order to leverage scheduled and  modernization maintenance. Program offices create plans, known as  aircraft availability improvement plans, based on these projections to  forecast improvements that can facilitate increased availability and  reduction of costs, among other things. The Air Force provides guidance  in the form of a template to ensure consistency amongst the plans, which  typically must include improvement initiatives with milestone goals. This  information includes projected aircraft availability rates for mission  capable, units possessed not reported, not mission capable for supply,  not mission capable for maintenance, and depot possession. Officials  noted that the program office creates an improvement plan each year,  regardless of whether it is short of its availability goal, since the plan  serves as a forecasting measure. The program is designed to ensure  the program offices have plans in place to meet target goals, and the  information and milestones laid out in the plans feed into the WSER  briefings to senior management. For example:

The B-52 plan for fiscal year 2017 discusses the process and  milestones for replacing actuator seals for the fleet, the costs of the  repair, and the expected benefit to B-52 availability—1.05 percent  improvement to the not mission capable supply metric.

The C-17 plan for fiscal year 2017 identifies the current and future  modifications, timelines for beginning and completion, and the effect  on availability. For example, the future replacement of a legacy  computer system with a modernized system and display is set to  begin in fiscal year 2019 with an estimated completion date of 2026.  This replacement is planned to be done concurrently with other  maintenance, and to prevent future declines in the C-17’s availability.

The F-22 plan for fiscal year 2017 identifies several projects taking  place between 2016 and 2021 that are expected to improve  availability by almost 2 percent.

Further, officials said they are currently working with the Assistant  Secretary of the Air Force (Acquisition) to develop an Air Force manual  that would make developing an Aircraft Availability Improvement Plan a  requirement. This manual will become a supplement to Air Force  Instruction 63-101/20-101, according to the officials.

Navy program offices for all seven fixed-wing aircraft in our review also  have plans for improving availability. According to Navy officials, they  started preparing “summary playbooks,” which is the Navy’s term for  improvement plans, in late 2015 and started implementing these plans in  early 2016 to increase aircraft availability. Officials told us that there was  a limitation in funding because of sequestration prior to fiscal year 2017,  which hampered their ability to fully implement the playbooks. At a broad  level, the Navy’s playbooks include efforts such as maintenance planning,  supply support, aircraft material condition and management, and  technical data, among other things. These efforts are linked to specific  initiatives such as working with the manufacturer and contractors to  provide maintenance support, identifying obsolete parts, conducting  aircraft fatigue analysis, and updating technical publications, among other  things, which have been identified by the program office as ways to  improve aircraft availability. Additionally, these playbooks include the  extent to which these initiatives are funded, underfunded, or partially  funded and the appropriation account that would fund each initiative. The  playbooks include the status of each initiative, and some of the playbooks  also provide an approximate time frame for implementing each initiative.  For example:

The playbook for the C-2A has a fatigue analysis initiative focused on  analyzing the landing gear to update its design, provide a depot repair  manual, and increase its service life, among other things. This  initiative is considered funded, is expected to improve aircraft  availability, and has an estimated time frame for implementation  between fiscal years 2017 and 2021.

The playbook for the E-2D contains a maintenance initiative focused  on improving the maintenance planning process of the C-2A, E-2C,  and E-2D aircraft by completing elements of the product support  package, such as training, publications, support equipment, and tools,  among others. This initiative is considered partially funded, is  expected to improve aircraft availability by decreasing the not mission- capable rates related to maintenance and supply and decreasing  maintenance down time, and has an estimated time frame for  implementation between fiscal years 2017 through 2019.

The playbook for the F/A-18A-D includes a product improvement  initiative to conduct a case study to assess the condition of the wiring  of the aircraft in the fleet. This initiative is considered funded and is  expected to help to sustain aircraft availability. However, there is no  time frame for implementing this initiative.

The playbook for the F/A-18E-F contains a service life modification  initiative focused on extending the service life of the aircraft through  modifications. According to officials, this initiative is considered  partially funded, is expected to help to sustain aircraft availability, and  is expected to help the fleet realize an 80 percent cost avoidance  because the Navy will not have to pay the cost to replace these  aircraft. Also, this initiative has an estimated time frame for  implementation between fiscal years 2018 through 2040.

The Departments of the Air Force and Navy spend tens of billions of  dollars each year to sustain their fixed-wing aircraft, which need  expensive logistics support, including maintenance and repair, to meet  goals for availability. The departments spent at least $20 billion annually  since 2011 to sustain the 12 aircraft that we examined. The Air Force and  Navy share a variety of sustainment challenges, including the age of their  aircraft as well as maintenance and supply support issues. These  challenges have led to half (6 of 12) of the aircraft in our review  experiencing decreasing availability and to the aircraft in general not  being able to meet aircraft availability goals. For example, 9 of 12 aircraft  did not meet availability goals in fiscal year 2016. These trends are  occurring even though the Air Force and Navy regularly review  sustainment metrics for the aircraft and are implementing plans for  improving aircraft availability. However, DOD’s policy and the Navy’s  guidance are not clear on whether the services should have a current  sustainment strategy for legacy weapon systems, including fixed-wing  aircraft, and on whether the strategies are required to be updated every 5  years. Without clarity about whether the DOD instruction and the Navy  guidance apply to legacy systems, program officials will not know whether  they are required to have a sustainment strategy or are required to  update the plan for their respective fixed-wing aircraft. Furthermore, the  program offices, the services, and DOD may not have full visibility of  necessary requirements to document program objectives, related risks,  and the effectiveness of the program, ultimately jeopardizing the  sustainability and affordability of each of the programs.

We are making the following two recommendations to DOD:  The Secretary of Defense should ensure that the Under Secretary of  Defense for Acquisition and Sustainment updates or issues new policy  clarifying the requirements for documenting sustainment strategies for  legacy weapon systems, including fixed-wing aircraft. (Recommendation  1)

The Secretary of the Navy should update or issue new guidance clarifying  the requirements for documenting sustainment strategies for legacy  weapon systems, including fixed-wing aircraft. (Recommendation 2)

We provided a draft of the sensitive report to DOD for review and  comment. In written comments that are reproduced in appendix XVI, DOD  concurred with our recommendations and noted planned actions to  address each recommendation. The Air Force and Navy also provided  technical comments, which we incorporated as appropriate.

We are sending copies of this report to the appropriate congressional  committees; the Secretary of Defense; the Secretaries of the Navy and  Air Force; the Commandant of the Marine Corps; the Under Secretary of  Defense for Acquisition and Sustainment; and the Director, Defense  Logistics Agency.

In addition, the report is available at no charge on the GAO website at  http://www.gao.gov. If you or your staff have questions about this report,  please contact me at merrittz@gao.gov or (202) 512-5257. GAO staff  who made key contributions to this report are listed in appendix XVII.

Appendix I: GAO’s Recent Prior Work on Sustainment Issues within the Department of Defense

Over the past several years, we have conducted work on a number of  issues that affect the ability of the Department of Defense (DOD) to  sustain its weapon systems. In September 2017, we found that several  factors were important to the success of Product Support Managers.  These factors included teamwork and collaboration, early implementation  of the Product Support Manager position, and organizational support and  emphasis on sustainment. We also found that in response to our 2014  recommendations regarding the implementation of the Product Support  Manager position, DOD had developed a comprehensive career path and  associated guidance to develop, train, and support future Product Support  Managers. Additionally, DOD revised guidance to define roles,  responsibilities, and reporting relationships between support staff and  Product Support Managers. However, DOD was still in the process of  implementing our other three recommendations, such as issuing clear,  comprehensive, centralized guidance regarding the roles and  responsibilities of PSMs and collecting and evaluating information on the  effects, if any, that Product Support Managers are having on life-cycle  sustainment decisions for their assigned weapon systems.

In September 2017, we also found that DOD does not have complete  information to identify and manage single-source-of-supply risks.  Specifically, some parts are provided by a single source of supply (e.g.,  one manufacturing facility), and if that single source were no longer able  to provide the part, DOD could face challenges in maintaining weapon  systems. DOD concurred with our six recommendations focused on  improving the completeness of information for single-source-of-supply  risks, including issuing department-wide policy that clearly defines  requirements of Diminishing Manufacturing Sources and Material  Shortages management, and details responsibilities and procedures to be  followed to implement the policy. DOD is in the process of taking action  to implement these recommendations.

In June 2016, we found that the Defense Logistics Agency and the  military services have not adopted metrics to measure the accuracy of  planning factors, such as the accuracy of part lists, or the costs created  by backorders. As a result, depot maintenance may not be efficient or  cost-effective, resulting in unnecessary delays in the repair of weapon  systems. DOD concurred with our six recommendations to develop  metrics to monitor the accuracy of demand planning factors and  disruption costs created by the lack of parts at depot maintenance sites  and is in the process of taking action to implement these  recommendations. For a listing of relevant past GAO work, see the  Related GAO Products list at the end of this report.

Sustainment: Depot maintenance  conducted organically at the  designated air logistics complex  and contractually for some depot- level repairs at contractor facilities.

The B-52 is a long-range, heavy bomber that can perform a variety of  missions, including strategic attack, close air support, air interdiction,  maritime operations, and offensive counter-air missions. It can carry nuclear  or precision-guided conventional ordnance with worldwide precision  navigation capability. However, the B-52s are some of the oldest aircraft in  the Air Force’s fleet, and will continue to operate until at least 2040 (see fig.  8). Operating and support (O&S) costs for the B-52s have remained relatively  steady, generally fluctuating around $1.2 billion–$1.3 billion per year. As a  predominantly military-maintained system, most of that O&S cost is related to  maintenance and manpower, with depot maintenance and depot-level  reparables—direct labor and materials for item repairs, transportation, and  storage, among other things—accounting for most of the maintenance cost.

Sustainment Challenges and Mitigation Actions

Technology Program (2014) is focused on upgrading outdated  communications technology. The communications modification requires  7,000 hours of work and is estimated to be complete by 2020. The fleet  has active sustainment plans for other components of the aircraft, such  as the B-52 Anti-skid Replacement Life Cycle Sustainment Plan (2015),  which is estimated to cost over $40 million and be completed by 2019.

The B-52 faces sustainment  challenges related to its age and,  according to officials, replacement  parts are difficult to obtain. Several  modernization efforts are under  way (communications, engines,  etc.), and is working with vendors  and its own service engineers to  identify problem areas and plan  ahead so that replacement parts  will be available.

Depot maintenance on the B-52 is managed by the program office and  conducted at Oklahoma City Air Logistics Complex depot.

This report is a public version of a sensitive report that we issued on April 25,  2018. DOD deemed some of the information, such as aircraft availability, not  mission capable rates, number of aircraft in depots, and budgeted and  executed flight hours to be sensitive (i.e., For Official Use Only). This public  report omits the information that DOD deemed to be sensitive.

In commenting on a draft of this assessment, the program office provided technical comments, which were incorporated where appropriate.

The C-17 is a long-range, heavy logistic transport aircraft powered by four  F-117 turbofan engines with air-refueling capability that was first  manufactured in 1987 (see fig. 10). It is capable of rapid strategic delivery of  troops and all types of cargo to main operating bases or to bases in any  forward deployment area. The C-17 can perform tactical airlift and airdrop  missions and can transport ambulatory patients during aeromedical  evacuations, when required. The C-17 can carry virtually all air-transportable  equipment. Total operating and support (O&S) costs for the C-17 have  decreased from about $5.3 billion in fiscal 2011 to about $4.0 billion in fiscal  year 2016. Specifically, unit operations decreased, while maintenance costs  have generally increased during this period due to contractor logistics  support because the C-17 is a predominantly contractor-managed aircraft.

Average number of flying hours: 13,141 hours per aircraft

Depot maintenance activity and squadron locations:

The C-17 Enterprise Life Cycle Management Plan and Life Cycle  Sustainment Plan (2014) documents current and future acquisition,  sustainment, and integration efforts of the aircraft. It also addresses  contractual arrangements and partnership support agreements between  Air Force, Boeing, and other service providers for aircraft sustainment.

Boeing provides continued sole-source life-cycle support for the C-17  under the terms of the Globemaster Integrated Sustainment Program  (2013). Under this program, Boeing is responsible for sustainment, to  include material management and depot maintenance support.

The C-17 participates in a virtual fleet arrangement, a global network of  43 additional C-17 aircraft, which allows participants total aircraft parts  access from any fleet participant worldwide.

The C-17 is an aircraft being  modified to meet its requirements  as well as to address maintenance  and supply issues. The Air Force’s  actions to mitigate these  challenges include processes to  increase the service life of the  aircraft, allowing managers to  quickly hire skilled workers for  critical positions, and locating other  vendor source for parts.

Logistics Complex, and at its facility in San Antonio; landing gear  overhaul occurs at Ogden Air Logistics Complex, and engine overhaul  occurs at Oklahoma City Air Logistics Complex in partnership with Pratt &  Whitney, the original equipment manufacturer on the F-117 turbofan  engine.

Sustainment: Depot maintenance  conducted by Northrop Grumman,  and field maintenance conducted  organically, by the National Guard.

The E-8C Joint Surveillance Target Attack Radar System (E-8C) was first  manufactured in 1967 (see fig. 12). Its primary mission is to provide theater  ground and air commanders with ground surveillance to support attack  operations and targeting that contributes to the delay, disruption, and  destruction of enemy forces. Total operating and support (O&S) costs for the  E-8C have generally increased from about $686 million in fiscal year 2011 to  about $734 million in fiscal year 2016. Specifically, maintenance cost has  increased partly because of increases in contractor logistics support since  the E-8C is maintained by Northrop Grumman.

E-8C aircraft were formerly used as commercial airliners and purchased  by the Air Force. Therefore, the exact usage of the aircraft was unknown  with any degree of specificity. The program office has utilized new  analysis conducted by Boeing to develop an improved method of  determining and tracking service life for the E-8C aircraft. The new  method uses a quantitative analysis capability to identify safety of flight  structural concerns, allowing for planning and execution of risk mitigation.

The E-8C is an aircraft with  significant maintenance and supply  issues according to Air Force  officials. The Air Force’s actions to  mitigate these challenges include  updating the Maintenance Plan and  the Corrosion Plan for the E-8C  (formerly a commercial airframe) to  bring them in line with military  standards.

Sustainment: Depot maintenance  conducted organically at the  designated air logistics complex,  and field maintenance conducted  organically and by contractors.

The F-16 Fighting Falcon is a compact, single-engine, multirole fighter  aircraft first manufactured in 1978 (see figure 14). It is highly maneuverable  and participates in air-to-air combat and air-to-surface attack. There are four  versions of the F-16: A, single-seat model; B, two-seat model with tandem  cockpits; C and D, single- and two-seat models, respectively, incorporating  newer capabilities. Total operating and support (O&S) cost for the F-16  decreased from about $5 billion in fiscal year 2011 to about $4 billion in  fiscal year 2016 because of a 6 percent reduction of inventory. Specifically,  maintenance cost has generally decreased during this same period as a  result of a decrease in cost of depot maintenance.

Manufacturer: Lockheed Martin and Boeing

Sustainment: Performance-based  logistics contract with depot  maintenance subcontracted to  Ogden Air Logistics Complex,  Utah, and field maintenance  performed organically. and is designed to project air dominance, rapidly and at great distances, and  defeat threats. Overall operating and support costs (O&S) for the F-22 have  decreased about $248 million overall since fiscal year 2011. Maintenance  issues continue to be an area of concern for the aircraft, and these costs  increased approximately $255 million from fiscal years 2011 to 2016, due to  increases in contractor logistics costs.

maintaining a comprehensive diminishing manufacturing sources  program and proactively supporting the continued sustainment of  component parts of the aircraft through various replacement programs,  such as the F-22 Reliability and Maintainability Maturation. This initiative  is an ongoing effort to drive continuous improvement in availability.

The F-22 faces issues with its low- observable coating and supply  funding. Actions to mitigate these  challenges include contracting a  repair facility to conduct coating  reversion repair and securing  additional spares funding.

The program office provided technical comments, which were incorporated as appropriate. The program noted the following: The Air Force and supporting industry are aggressively addressing sustainment challenges by investing in improvements to improve durability and maintainability, to include the low-observable coating. Additionally, for fiscal year 2017, 14.5 percent of not mission capable for maintenance aircraft have been available for pilots to fly. Also, supply chains are built on a network of partnerships that optimally thrive on consistent and predictable workflows. When unplanned changes occur in budgets, the forecasted flying hours, or major target objectives like AA, it creates major effects on the supply networks and there is rarely a quick fix. Another challenge affecting F-22 sustainment cost-effectiveness and responsiveness is the exit of many second- and third-tier suppliers driven by a lower business demand due to a significantly reduced fleet size (186 from the original 750 planned). The program office expects sustainment costs to stabilize as investments in fleet-wide repair processes and improved materials come to fruition.

The AV-8B Harrier (AV-8B) is a Vertical/Short Take-off and Landing attack  aircraft first manufactured in 1984 (see fig. 18).  The AV-8B has the capability  of conducting close air support using conventional weapons for intermediate  range intercept and attack missions. The AV-8B is capable of deploying and  operating on aircraft carriers and other suitable seagoing platforms,  advanced bases, expeditionary airfields, and remote tactical landing sites.  Total operating and support (O&S) costs for the AV-8B have decreased from  about $815 million in fiscal year 2011 to about $646 million in fiscal year  2016. Specifically, unit-level manpower and operations as well as  maintenance costs have decreased partly because the inventory is  decreasing as AV-8B squadrons transition to the F-35 Joint Strike Fighter.

Average number of flying hours:  4,711 hours per aircraft  Operating and support cost:  $646 million  Depot maintenance activity and  squadron locations:

AV-8B Program Strategic Sustainment and Warfighting Relevance Plan  (2013) addresses strategic sustainment and warfighting requirements to  ensure relevance, reliability, safety, and sustainability through five pillars:  recruit and retain high-quality people, develop a comprehensive  readiness and sustainment plan, meet combatant commander  requirements, retain and sustain government and industry agencies to  support engineering and logistics requirements, and integrate capabilities  to remain tactically relevant and operationally effective.

AV-8B is maintained organically at Navy Fleet Readiness Centers under  planned maintenance intervals occurring every 1,500 flight hours; supply  support is provided organically by Naval Supply Systems Command and  Defense Logistics Agency; contractor support services are provided by  Boeing.

The AV-8B is operating beyond its planned service life with maintenance and supply issues. The Marine Corps’ actions to mitigate these challenges include moving aircraft to deploying squadrons, upgrading aircraft components, and locating other vendor sources for parts.

This report is a public version of a sensitive report that we issued on April 25,  2018. DOD deemed some of the information, such as aircraft availability, not  mission capable rates, number of aircraft in depots, and budgeted and  executed flight hours to be sensitive (i.e., For Official Use Only). This public  report omits the information that DOD deemed to be sensitive.

Manufacturer:  Grumman  Corporation (acquired by Northrop  Grumman)

The C-2A Greyhound Logistics Aircraft (C-2A) is a high-wing, twin-engine  monoplane cargo aircraft first manufactured in 1965 (see fig. 20). It is  designed to land on aircraft carriers, with a primary mission of providing  critical logistics support to Carrier Strike Groups by transporting high-priority  cargo, mail, and passengers between carriers and shore bases. The original  C-2A aircraft were overhauled to extend their operational life in 1973 and  again from 2004 through 2011. Total operating and support (O&S) costs for  the C-2A have generally decreased from about $233 million in fiscal year  2011 to about $207 million in fiscal year 2016. Specifically, unit-level  manpower, unit operations, and continuing system improvements have  decreased, while maintenance costs have increased.

Fiscal Year 2016 Data Average age: 29 years

Average number of flying hours: 10,117 hours per aircraft

Operating and support cost: $207 million

landing gear, and avionics system, among others. The Navy will include  an appendix for the C-2A when it updates the sustainment strategy for  the E 2D for its 5-year update.

C-2A completed a service life extension program from 2004 through 2011  to increase flight hours from 10,000 to 15,000 and landings from 16,020  to 36,000, among other things.

Aircraft are maintained organically by field maintainers and at Navy Fleet  Readiness Centers under a planned maintenance interval cycle with  three planned maintenance interval events occurring consecutively every  24 months, and supply support is provided organically by the Naval  Supply Systems Command and Defense Logistics Agency.

The C-2A is operating beyond its planned service life with maintenance and supply issues. The Navy’s actions to mitigate these challenges include moving aircraft to deploying squadrons, training maintainers to transition to vacated positions, and locating other vendor sources for parts.

The E-2 Hawkeye (E-2C) is the Navy’s all-weather, carrier-based tactical  battle management, surface surveillance coordination and airborne early  warning, command and control aircraft, with a planned sunset in 2026 when  the last E-2D is delivered (see fig. 22). The E-2 is a twin-engine, five- crewmember, high-wing turboprop aircraft with a 24-foot diameter radar  rotodome attached to the upper fuselage. Total operating and support (O&S)  costs for the E-2 have decreased from about $536 million in fiscal year 2011  to about $345 million in fiscal year 2016. Specifically, unit manpower and  maintenance costs have decreased, partly because E-2C inventory is  decreasing as E-2C squadrons transition to the E-2D fleet.

Fiscal Year 2016 Data Average age: 16 years

Average number of flying hours: 5,839 hours per aircraft

Operating and support cost: $345 million

comprehensive sustainment logistics, engineering programs, and financial  resources necessary to ensure continued platform sustainment and  attainment of readiness and safety operations. The Navy will include an  appendix for the E-2C when it updates the sustainment strategy for the E-2D  for its 5-year update.

E-2C is maintained organically by field maintainers and at Navy Fleet  Readiness Centers under a planned maintenance interval cycle: initial  planned maintenance interval is performed by field maintainers at 42 months  and the second cycle is performed at a Fleet Readiness Center 46 months  after the initial planned maintenance interval. Supply support is provided  organically by the Naval Supply Systems Command and Defense Logistics  Agency; contractor support services are provided by General Dynamics and  Wyle Labs.

The E-2C is operating beyond its planned service life with maintenance and supply issues. The Navy’s actions to mitigate these challenges include transitioning E-2C squadrons to the E-2D fleet, conducting studies to identify maintenance tasks to mitigate potential failures, and waiting for parts to be available.

The E-2 Advanced Hawkeye (E-2D) is the newest variant of the E-2 aircraft  platform, expecting to reach full operational capability by 2027 (see fig. 24).  Using the same configuration as the E-2C, the E-2D aircraft is used for  surface-surveillance coordination and airborne early warning, and command  control. Its mission is to provide advanced warning of approaching enemy  surface units, and cruise missiles and aircraft, among other things. Total  operating and support (O&S) costs for the E-2D have increased consistently  since fiscal year 2011 to about $125 million in fiscal year 2016. This increase  is driven by the addition of aircraft to the inventory as the Navy continues to  produce E-2D aircraft through 2026.

As a new aircraft, the E-2D is experiencing maintenance and supply issues. The Navy’s actions to mitigate these challenges include troubleshooting component failures, and cannibalizing parts— moving parts from one aircraft to another.

The EA-18G Growler is the fourth major variant of the F/A-18 family of  aircraft manufactured in 2007 to replace the EA-6B Prowler (see fig. 26). The  EA-18G is the first newly designed electronic warfare aircraft produced in  more than 35 years and combines the proven F/A-18 Super Hornet platform  with a sophisticated electronic warfare suite. Total O&S costs for the EA-18G  have consistently increased from about $334 million in fiscal year 2011 to  about $868 million in fiscal year 2016. Specifically, unit manpower and  maintenance costs have increased partly because the inventory is  increasing, as EA-18Gs are still in production.

Fiscal Year 2016 Data Average age: 5 years

Average number of flying hours: 1,489 hours per aircraft

design, development, and fielding of the aircraft. Some of the key support  program elements include developing support equipment and technical  data, testing requirements for avionics, and facilities requirements,  among others. The Navy is updating this plan and expects to finalize it in  2018.

The aircraft are maintained organically at Navy Fleet Readiness Centers  under planned maintenance intervals, which typically occur every 72  months. Also, the Navy partners with Boeing to provide wholesale supply  and depot repair support for major components, such as the engine.

Sustainment Challenges and Mitigation Actions

In commenting on a draft of this assessment, the program office provided technical comments, which were incorporated where appropriate.

The F/A-18A-D Hornet Strike Fighter is a twin-engine, mid-wing, multimission  tactical aircraft initially fielded in the 1980s (see fig. 28). In its fighter mode, it  is used primarily as a fighter escort and for air defense; in its attack mode, it  is used for force projection, interdiction, and air support. Total operating and  support (O&S) costs for the F/A-18A-D have decreased consistently from  about $3.1 billion in fiscal year 2011 to about $2.4 billion in fiscal year 2016.  Specifically, unit manpower, operations, and maintenance costs have  decreased, partly because the F/A-18A-Ds are being permanently  transitioned out of service to be replaced by the F-35 Joint Strike Fighter..

Operating and support cost: $2.4 billion

and financial resources necessary to ensure continued readiness and  supportability for the remainder of the aircraft’s service life. The Navy is  currently updating this plan and expects to finalize it in 2018.

Depot maintenance activity and squadron locations:

The aircraft are maintained organically at Navy Fleet Readiness Centers  under planned maintenance intervals, which typically occur every 48  months for carrier-deploying aircraft, and every 72 months for land-based  aircraft.

The Navy implemented the High-Flight-Hour program in 2006 to extend  the service life from 8,000 to 10,000 flight hours by inspecting and  repairing airframes, and replacing major components and parts. The  High-Flight-Hour program, along with other factors, has led to  maintenance carryover (i.e., into the next fiscal year) due to maintenance  events taking longer than planned.

In 1999, the Navy entered into a contract with Boeing for engineering  support to leverage resources within the technology and industrial base  to improve efficiency of the maintenance process and address the  maintenance backlog.

The F/A-18A-D is operating beyond  its planned service life with  maintenance and supply issues.  The Navy’s actions to mitigate  these challenges include extending  the service life of the aircraft,  allowing maintainers to work  overtime to reduce backlog, and  cannibalizing parts—moving parts  from one aircraft to another.

This report is a public version of a sensitive report that we issued on April 25,  2018. DOD deemed some of the information, such as aircraft availability, not  mission capable rates, number of aircraft in depots, and budgeted and  executed flight hours to be sensitive (i.e., For Official Use Only). This public  report omits the information that DOD deemed to be sensitive.

The F/A-18E-F Super Hornet was first manufactured in 1998 (see fig. 30).  The F/A-18E-F is highly capable across the full mission spectrum: air  superiority, fighter escort, reconnaissance, aerial refueling, close air support,  air defense suppression, and day/night precision strike. The F/A-18E-F  provides aircrew the capability and performance necessary to face 21st  century threats. Total operating and support (O&S) costs for the F/A-18E-4  have increased from about $2.2 billion in fiscal year 2011 to about $3.1 billion  in fiscal year 2016. Specifically, unit manpower, maintenance, and continuing  system support have increased, partly because the inventory is increasing,  as the F/A-18E-F is still in production.

the Navy is conducting an assessment to determine the number of flight  hours the aircraft can safely continue to fly, and then extend the service  life of the program through inspections, repairs, and modifications,  among other things. The Navy contracted with Boeing to potentially begin  these efforts by fiscal year 2018.

The F/A-18E-F is a high  operational tempo aircraft  supporting contingency operations  with maintenance and supply  issues. The Navy’s actions to  mitigate these challenges include  plans to extend the service life of  the aircraft, training maintainers to  transition to vacated positions, and  cannibalizing parts—removing  parts from one aircraft to another.

To examine the trends in aircraft availability and operating and support  (O&S) costs for selected Air Force and Navy fixed-wing aircraft, including  whether the aircraft met availability goals, we selected a nongeneralizable  sample of 12 fixed-wing aircraft managed by the Departments of the Air  Force and the Navy. These included two Marine Corps aircraft that are  managed by the Department of the Navy. This nongeneralizable sample  was selected to ensure a mix of aircraft, including type of aircraft (fighter,  bomber, cargo, etc.), age of the aircraft, and size of inventory, and  whether the aircraft were sustained organically by the Department of  Defense (DOD) or through contract arrangements, such as public-private  partnerships or performance-based logistics, among other factors.

For the Air Force, we selected five fixed-wing aircraft—the B-52  Stratofortress, C-17 Globemaster III, E-8C Joint Surveillance and Target  Attack Radar System (JSTARS), F-16 Fighting Falcon, and F-22 Raptor.  For the Navy, including the Marine Corps, we selected seven fixed-wing  aircraft—the AV-8B Harrier, C-2A Greyhound Logistics Aircraft, E-2  Hawkeye Early Warning and Control Aircraft, E-2 Advanced Hawkeye  Early Warning and Control Aircraft, EA-18G Growler, F/A-18 Hornet  Strike Fighter A-D, and F/A-18 Super Hornet E-F. The Marine Corps uses  the AV-8B Harrier and also uses a variant of the F/A-18A-D. For the  selected aircraft, we obtained and reviewed the aircraft availability,  sustainment, and O&S data for accuracy and completeness, interviewed  officials regarding their data-collection processes, and reviewed available  related policies and procedures associated with the collection of the data.  As a result, we found the information to be sufficiently reliable for the  purposes of presenting sustainment metrics, such as aircraft availability  and O&S costs. status due to maintenance, supply, and both. With respect to O&S costs,  we collected and analyzed data from fiscal years 2011 through 2016.

We conducted data-reliability assessments for the data provided by the  Air Force and the Navy. To do this, we sent data-reliability questionnaires  to both departments requesting information on the sources that generated  the data. For the Air Force, we conducted data-reliability assessments on  the Air Force Total Ownership Cost system and the Logistics Installation  and Mission Support system. For the Navy, we conducted data-reliability  assessments on the Aviation Management Supply and Readiness  Reporting—Type Model Series Integrated Database, the Decision  Knowledge Programming for Logistics Analysis and Technical Evaluation  system, the Flying Hour Projection System / Cost Adjustment and  Visibility Tracking System, and the Visibility and Management of  Operating and Support Costs system. We reviewed responses from both  departments on these sources as well as documentation—such as  guidance, user manuals, and data dictionaries—provided to corroborate  questionnaire responses, and interviewed knowledgeable officials to  discuss the data. We concluded that the data provided by the Air Force  and the Navy were sufficiently reliable for the purposes of reporting  condition metrics such as aircraft availability; not mission capable status  due to maintenance, supply, and both; depot inductions; budgeted and  executed flight hours; and O&S costs for the selected fixed-wing aircraft  in our review.

To identify the sustainment challenges and mitigation actions for the  selected aircraft, we reviewed sustainment metrics data, performance  briefings, and other relevant documentation to identify specific challenges  for each of the 12 aircraft in our review. We also reviewed ongoing and  planned actions to address those challenges. Additionally, we interviewed  program officials, depot officials, field maintainers, and squadron  personnel to obtain their views on the challenges they face in sustaining  the aircraft and the actions they take to mitigate those challenges. In  some instances, we visited depots and squadrons to observe aircraft  undergoing maintenance, discuss the respective maintenance processes,  and discuss challenges and mitigation actions with officials. We then  grouped the identified challenges into categories and represented them in  a table to demonstrate which aircraft are experiencing specific  challenges.

To assess the extent to which the Air Force and the Navy have  sustainment strategies, regularly review sustainment metrics, and have  plans to improve aircraft availability for the selected fixed-wing aircraft, we  obtained and analyzed sustainment strategies, performance management  frameworks (i.e., sustainment metrics collected and monitored as well as  the levels of management review), and improvement plans for each of the  selected 12 fixed-wing aircraft.

We also identified and reviewed DOD, Air Force, and Navy guidance to  analyze the departments’ efforts in sustaining these aircraft and to  determine whether these were consistent with federal standards for  internal control that deal with management defining objectives in specific  terms. Specifically, we reviewed DOD Instruction 5000.02, Operation of  the Defense Acquisition System, which provides management principles  and mandatory policies for defense acquisition systems such as fixed- wing aircraft. These policies incorporate decision processes and  assessing of readiness, which includes the creation of and requirements  for a Life-cycle Sustainment Plan. We also reviewed Air Force Instruction  63-101/20-101, Integrated Life Cycle Management, which implements  various Air Force and DOD policy directives, including DOD Instruction  5000.02. It establishes the integrated life-cycle management guidelines  and procedures for Air Force personnel who develop, review, approve, or  manage the systems, subsystems, end-items, services, and activities  procured by the Air Force. For the Navy, we reviewed Secretary of the  Navy M-5000.2, Department of the Navy Acquisition and Capabilities  Guidebook, which provides guidance for the operation of the defense  acquisition system and the joint capabilities integration and development  system. It also implements DOD Instruction 5000.02 for the Navy and  Marine Corps, including guidance on the management and execution of a  sustainment strategy. and service guidance. We also reviewed the Air Force’s and the Navy’s  performance metric briefings and improvement plans to determine  whether the departments regularly reviewed sustainment metrics and had  plans aimed at improving aircraft availability. We interviewed DOD, Air  Force, and Navy officials knowledgeable about sustainment of these  selected fixed-wing aircraft to discuss DOD’s and the departments’ efforts  in sustaining these aircraft, including historical information on each  aircraft, applicability of policy and guidance for legacy aircraft, and  overviews of performance management frameworks identified by the  departments to monitor and improve aircraft availability.

To develop the fixed-wing aircraft sustainment summary documents (i.e.,  “Sustainment Quick Looks”) in appendixes II–XIII we obtained historical  and current information including background on aircraft capabilities,  manufacturer, sustainment strategy, depot maintenance and squadron  locations, and key dates in the life cycle of each aircraft (i.e., first  manufactured, initial and full operational capability, last production, and  planned sunset year). We collected and analyzed the following metrics: aircraft availability, not mission capable maintenance, not mission  capable supply, and not mission capable aircraft from fiscal year 2011  through March 2017;  the number of aircraft in depots for fiscal years 2011 through 2016; budgeted and executed flight hours from fiscal years 2011 through overall O&S and maintenance costs for fiscal years 2011 through  2016.

We compared availability actuals to goals, aircraft in depots to availability  trends, and budgeted and executed flight hours to availability trends. We  analyzed O&S cost by reviewing its six elements and compared them to  availability trends. We also analyzed the subcategories of the  maintenance costs element. Through interviews with knowledgeable  officials and reviewing documentation, we identified sustainment  challenges (i.e., aging, maintenance and supply support) and mitigation  actions to address these challenges for each selected fixed-wing aircraft.  DOD deemed some of the information, such as aircraft availability, not  mission capable status, number of aircraft in depots, and budgeted and  executed flight hours, to be sensitive (i.e., For Official Use Only), which  must be protected from public disclosure. This public report omits the  information that DOD deemed to be sensitive.

Additionally, to support our work for each objective we conducted site  visits and interviewed officials to discuss data trends and identify specific  sustainment challenges such as aging, maintenance, and supply support,  among other challenges affecting aircraft availability, and mitigation  actions to address these challenges. For the Air Force, we met with the  following entities:

Headquarters—Secretary of the Air Force, Logistics and Product  Support and Deputy Assistant Secretary for Cost and Economics, Air  Force Cost Analysis Agency;

Materiel Commands—Air Force Materiel Command and Air Force  Life Cycle Management Center;

Program Offices—B-52 Program Office, C-17 Program Office, E-8C  Program Office, F-16 Program Office, and F-22 Program Office;

Depots—Tinker Air Force Base at Oklahoma City, Oklahoma (B-52);  Robins Air Force Base at Warner Robbins, Georgia (C-17); Northrop  Grumman facility at Lake Charles, Louisiana (E-8C); Ogden Air  Logistics Center / Hill Air Force Base at Ogden, Utah (F-16 and F-22);  and

Squadrons—437th Maintenance Group, Joint Base Charleston,  South Carolina (C-17); 461st Air Control Wing, Robins Air Force Base  Georgia (E-8C); 20th Fighter Wing, Shaw Air Force Base, South  Carolina (F-16); and 325th Maintenance Group, Tyndall Air Force  Base, Florida (F-22).

For the Navy, we met with the following entities:

Headquarters—Deputy Assistant Secretary of the Navy— Expeditionary Programs and Logistics Management, Marine Corps  Aviation Plans and Policy Branch, and Air Warfare Division;

Materiel Commands—Commander, Fleet Readiness Center; Naval  Air Systems Command; and Naval Supply Systems Command;

Program Offices—Program Manager–Air (PMA)-231 (C-2A, E-2C,  and E-2D); PMA- 257 (AV-8B); and PMA-265 (F/A-18A-F, and EA- 18G);

Depots—Fleet Readiness Center–East at Cherry Point, North  Carolina; Fleet Readiness Center–Mid Atlantic at Naval Air Station  Norfolk, Virginia, and Naval Air Station Oceana, Virginia;

Squadrons—Marine Corps Air Station Cherry Point, North Carolina;  Marine Corps Air Station Miramar, California; Naval Air Station  Norfolk, Virginia; and Naval Air Station Oceana, Virginia; and

Appendix XV: Air Force and Navy Average Operating and Support Cost per Aircraft for Selected Fixed-Wing Aircraft

For fiscal year 2016, total operating and support (O&S) costs for the five  Air Force fixed-wing aircraft selected in our review were about $12 billion,  and the average O&S cost per aircraft across all five fleets was about $96  million, as shown in figure 32. Each of the C-17 and F-16 fleets  accounted for about 33 percent of the total O&S cost, and the E-8C’s  average cost per aircraft accounted for about 48 percent of the total  average cost per aircraft.

For fiscal year 2016, total O&S costs for the seven Navy fixed-wing  aircraft selected in our review were about $7.7 billion, and the average  O&S cost per aircraft across all seven fleets was about $44 million, as  shown in figure 33. The F/A-18E-F fleet accounted for about 40 percent of  the total O&S cost, and the E-2C’s average cost per aircraft accounted for  about 19 percent of the total average cost per aircraft.

Appendix XVI: Comments from the Department of Defense

Appendix XVII: GAO Contact and Staff Acknowledgments

In addition to the contact named above, John Bumgarner (Assistant  Director), Clarine Allen, Ron Aribo, Vincent Buquicchio, Amie Lesser,  Richard Powelson, Steven Putansu, Matt Spiers, and Natasha Wilder  made key contributions to this report.

Defense Supply Chain: DOD Needs Complete Information on Single  Sources of Supply to Proactively Manage the Risks. GAO-17-768.  Washington, D.C.: September 27, 2017.

Weapon Systems Management: Product Support Managers’ Perspectives  on Factors Critical to Influencing Sustainment-Related Decisions.  GAO-17-744R. Washington, D.C.: September 12, 2017.

Defense Acquisitions: Assessments of Selected Weapon Programs.  GAO-17-333SP. Washington, D.C.: March 30, 2017.

Depot Maintenance: Executed Workload and Maintenance Operations at  DOD Depots. GAO-17-82R. Washington, D.C.: February 3, 2017.

Defense Inventory: Further Analysis and Enhanced Metrics Could  Improve Service Supply and Depot Operations. GAO-16-450.  Washington, D.C.: June 9, 2016.

Weapon Systems Management: DOD Has Taken Steps to Implement  Product Support Managers but Needs to Evaluate Their Effects.  GAO-14-326. Washington, D.C.: April 29, 2014.