Sec. 78.17. Qualifications to start and run engines and to taxi aircraft

No person shall start or run an aircraft engine at the airport, or taxi an aircraft on the airport, unless he is a pilot licensed by the Federal Aviation Administration to operate that particular type and class of aircraft, or an aircraft and powerplant mechanic licensed by the Federal Aviation Administration and qualified to start, run the engines, and taxi that particular aircraft, shall be attending the controls. Wheel chocks, or other approved devices, for blocking the movement of an aircraft shall always be placed at the front and rear of each main landing gear and the brakes of the aircraft shall be on and locked before the engine or engines are started, except in cases where, in the opinion of the airport operator, other proven procedures are equally safe.