def airspeed_energy_error(NAV_CONTROLLER_OUTPUT, VFR_HUD):
    """return airspeed energy error matching APM internals
    This is positive when we are going too slow
    """
    aspeed_cm = VFR_HUD.airspeed * 100
    target_airspeed = NAV_CONTROLLER_OUTPUT.aspd_error + aspeed_cm
    airspeed_energy_error = (target_airspeed * target_airspeed - aspeed_cm *
        aspeed_cm) * 5e-05
    return airspeed_energy_error
