question: Pilot of g.v. alfyorov, and a Record description of altitude with kg (lb) payload, and a Type of mi-10 involved what date?
answer: SELECT date FROM table_name_39 WHERE pilot = "g.v. alfyorov" AND record_description = "altitude with kg (lb) payload" AND type = "mi-10"
context: CREATE TABLE table_name_39 (date VARCHAR, type VARCHAR, pilot VARCHAR, record_description VARCHAR)