def phugoid_rating(phugoid_damping, ph_t2):
    """ Give a rating of the phugoid mode : Level1 Level2 or Level 3 according to MILF-8785C
    Args:
        phugoid_damping (float) : [-]
        ph_t2 (float):  phugoid time to double amplitude [s]

    Returns:
        1 one 2 or 3 corresponding to the flight level
    """
    if 0.04 < phugoid_damping :
        ph_rate = 1
    elif 0 < phugoid_damping < 0.04 :
        ph_rate = 2
    elif 55 <= ph_t2 :
        ph_rate = 3
    else:
        ph_rate = None

    return ph_rate