Section 121.579 - Minimum altitudes for use of autopilot(a)Definitions. For purpose of this section- (1) Altitudes for takeoff/initial climb and go-around/missed approach are defined as above the airport elevation.(2) Altitudes for enroute operations are defined as above terrain elevation.(3) Altitudes for approach are defined as above the touchdown zone elevation (TDZE), unless the altitude is specifically in reference to DA (H) or MDA, in which case the altitude is defined by reference to the DA(H) or MDA itself.(b)Takeoff and initial climb. No person may use an autopilot for takeoff or initial climb below the higher of 500 feet or an altitude that is no lower than twice the altitude loss specified in the Airplane Flight Manual (AFM), except as follows- (1) At a minimum engagement altitude specified in the AFM; or(2) At an altitude specified by the Administrator, whichever is greater.(c)Enroute. No person may use an autopilot enroute, including climb and descent, below the following-(2) At an altitude that is no lower than twice the altitude loss specified in the AFM for an autopilot malfunction in cruise conditions; or(3) At an altitude specified by the Administrator, whichever is greater.(d)Approach. No person may use an autopilot at an altitude lower than 50 feet below the DA(H) or MDA for the instrument procedure being flown, except as follows- (1) For autopilots with an AFM specified altitude loss for approach operations-(i) An altitude no lower than twice the specified altitude loss if higher than 50 feet below the MDA or DA(H);(ii) An altitude no lower than 50 feet higher than the altitude loss specified in the AFM, when the following conditions are met- (A) Reported weather conditions are less than the basic VFR weather conditions in § 91.155 of this chapter;(B) Suitable visual references specified in § 91.175 of this chapter have been established on the instrument approach procedure; and(C) The autopilot is coupled and receiving both lateral and vertical path references;(iii) An altitude no lower than the higher of the altitude loss specified in the AFM or 50 feet above the TDZE, when the following conditions are met- (A) Reported weather conditions are equal to or better than the basic VFR weather conditions in § 91.155 of this chapter; and(B) The autopilot is coupled and receiving both lateral and vertical path references; or(iv) A greater altitude specified by the Administrator.(2) For autopilots with AFM specified approach altitude limitations, the greater of- (i) The minimum use altitude specified for the coupled approach mode selected;(iii) An altitude specified by Administrator.(3) For autopilots with an AFM specified negligible or zero altitude loss for an autopilot approach mode malfunction, the greater of- (ii) An altitude specified by Administrator.(4) If executing an autopilot coupled go-around or missed approach using a certificated and functioning autopilot in accordance with paragraph (e) in this section.(e)Go-Around/Missed Approach. No person may engage an autopilot during a go-around or missed approach below the minimum engagement altitude specified for takeoff and initial climb in paragraph (b) in this section. An autopilot minimum use altitude does not apply to a go-around/missed approach initiated with an engaged autopilot. Performing a go-around or missed approach with an engaged autopilot must not adversely affect safe obstacle clearance.(f)Landing. Notwithstanding paragraph (d) of this section, autopilot minimum use altitudes do not apply to autopilot operations when an approved automatic landing system mode is being used for landing. Automatic landing systems must be authorized in an operations specification issued to the operator.Doc. No. FAA-2012-1059, 79 FR 6086 , Feb. 3, 2014