Airplane engines vary substantially and specific procedures for engine starting must be accomplished in reference to approved engine start checklist as detailed in the airplane’s AFM/POH. However, some generally accepted hazard mitigation practices and procedures are outlined.
Prior to engine start, the pilot must ensure that the ramp area surrounding the airplane is clear of persons, equipment, and other hazards from coming into contact with the airplane or the propeller. Also, an awareness of what is behind the airplane prior to engine start is standard practice. A propeller or other engine thrust can produce substantial velocities, result in damage to property, and injure those on the ground. The hazard of debris being blown into persons or property must be mitigated by the pilot. At all times before engine start, the anti-collision lights should be turned on. For night operations, the position (navigation) lights should also be on. Finally, just prior to starter engagement, the pilot should always call “CLEAR” out of the side window and wait for a response from anyone who may be nearby before engaging the starter.
When activating the starter, the wheel brakes must be depressed and one hand is to be kept on the throttle to manage the initial starting engine speed. Ensuring that properly operating brakes are engaged prior to starter engagement prevents the airplane from rapidly lunging forward. After engine start, the pilot manipulates the throttle to set the engine revolutions per minute (rpm) at the AFM/POH prescribed setting. In general, 1,000 rpm is recommended following engine start to allow oil pressure to rise and minimize undue engine wear due to insufficient lubrication at high rpm. It is important in low temperatures that an airplane engine use the proper grade of oil for the operating temperature range and engine preheat when temperatures approach and descend below freezing.
The oil pressure must be monitored after engine start to ensure that pressure is increasing toward the AFM/POH specified value. The AFM/POH specifies an oil pressure range for the engine, if the limits are not reached and maintained, serious internal engine damage is likely. In most conditions, oil pressure should rise to at least the lower limit within 30 seconds. To prevent damage, the engine should be shut down immediately if the oil pressure does not rise to the AFM/POH values within the required time.
Engine starters are electric motors designed to produce rapid rotation of the engine crankshaft for starting. These electric motors are not designed for continuous duty and should the engine not start readily, avoid continuous starter operation for periods longer than 30 seconds without a cool down period of at least 30 seconds to 1 minute (some AFM/POH specify times greater than these given). Engine starter motors service life is drastically shortened from high heat through overuse.
Although quite rare, the starter motor may remain electrically and mechanically engaged after engine start. This can be detected by a continuous and very high current draw on the ammeter. Some airplanes also have a starter engaged warning light specifically for this purpose. The engine should be shut down immediately if this occurs.
The pilot should be attentive for sounds, vibrations, smell, or smoke that are not consistent with normal operational experience. Any concerns should lead to a shutdown and further investigation.