Commercial pilot · ACS CA.II.C
Engine Starting
Engine starting is brief, but it's where ramp injuries happen and where engine problems first show up. Commercial airplanes are often fuel-injected, which makes hot starts their own skill.
Why this one matters
Propeller strikes are among the most preventable injuries in aviation, and a botched start can damage an expensive engine. On the ramp with passengers and line staff nearby, a disciplined start protects people first and the engine second.
Can’t miss
- •Follow the POH start procedure for the condition: normal, cold, hot, flooded, and, for fuel-injected engines, the specific hot-start technique.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Look around, turn on the beacon, call "Clear!" and wait before engaging the starter.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Treat every propeller as live: a broken magneto ground wire can let the engine fire when the propeller is moved.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Oil pressure must rise within the POH time limit: typically about 30 seconds in normal weather, and up to about twice that in very cold weather, when the oil is thick. If it hasn't risen by the POH limit for the conditions, shut down.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations; Your airplane's POH/AFM)
- •Respect starter duty limits: they vary widely (10-second bursts in some types, 30 seconds with minutes of cooling in others). Know your airplane's numbers and follow them.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations; Your airplane's POH/AFM)
- •External power: connect a ground power unit only as the POH describes, at the right voltage, and disconnect before taxi.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- •Position the airplane so the propeller blast won't hit people, aircraft or buildings, and not over loose gravel.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.C.S1)
What you should know
Starting in different conditions K1 · K2
- Normal start: by the checklist; brakes set or held, master on, beacon on, fuel pump and mixture as the POH says, "Clear!", starter, with one hand on the throttle to catch a surge. After start, set the POH idle (often about 1,000 RPM), don't let it race, and check oil pressure first, then the charging system and the other indications.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Cold weather: preheat below the temperature the manufacturer specifies; cold oil is thick and batteries are weak.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Hot fuel-injected engine: fuel vaporizes in the lines (vapor lock). The hot-start procedure is specific to the engine and airframe: many purge vapor with the fuel pump at idle cutoff; some crank at idle cutoff and advance the mixture only as it fires. Don't prime it like a cold or carbureted engine; use your POH's exact sequence.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Flooded engine: usually mixture idle cutoff and throttle open while cranking, then mixture rich as it fires, per the POH.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- External power: when the battery is weak, a ground power unit can start the engine. Use the POH procedure and correct voltage, and have the unit disconnected and clear before taxi.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
Limits and when to stop K3
- Crank for the POH time limit, then let the starter cool; repeated long cranking overheats it.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- No oil pressure within the POH time (often about 30 seconds; in very cold weather the POH may allow up to about 60, because cold oil is slow): shut down.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- If the starter stays engaged after the engine starts, shut down.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Engine fire during start, as the POH directs: keep cranking to draw the flames in while cutting off the fuel (mixture idle cutoff, throttle open, fuel pump and selector off). If it starts, run it briefly, then shut down and inspect. If it doesn't, or the fire persists, stop cranking, finish the POH fire procedure, get everyone out, fight it from outside, and don't try another start.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations; Your airplane's POH/AFM)
Propeller safety R1
- Never move a propeller casually: a broken P-lead means a magneto isn't grounded and can fire the engine with the switch off.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
- Brief passengers to stay clear of the propeller arc when boarding and leaving, and never start with someone near the airplane.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.B.S2)
- Hand-propping is never done alone: two trained people who both know the airplane and the technique, one pulling the propeller and calling the steps, the other at the controls, who knows them thoroughly, with the brakes set and the airplane chocked or tied down. Agree the calls ("fuel on, switch off, throttle closed, brakes set"; "contact") before starting.(Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations)
On the flight
ACS standards
- Position the airplane considering structures, other aircraft, wind, and the safety of people and property nearby; complete the checklists.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.II.C.S1-S2)
What your instructor is watching for
Your instructor watches for a real look around and a loud "Clear!", brakes held, oil pressure checked right after start, and the correct technique for a hot fuel-injected engine.
Scenarios
Decide what you would do first, then see the worked answer.
The battery is too weak to crank, and the FBO offers a ground power unit.
How do you proceed? See the worked answer
Use the POH external-power procedure with the correct voltage. Afterward, consider why the battery was weak: an alternator problem could leave you without electrical power in flight.
Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations
Oil pressure is still at zero 30 seconds after a start on a mild morning.
What do you do? See the worked answer
Shut down at the POH limit for the conditions (often about 30 seconds in normal weather; longer is allowed only in very cold weather if the POH says so) and have maintenance check it. Running without oil pressure can destroy the engine in minutes.
Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations
A line worker walks toward the propeller as you're about to start.
What do you do? See the worked answer
Don't start. Wait until they're well clear and acknowledge you, look around again, call "Clear!", then start.
Airplane Flying Handbook (FAA-H-8083-3C), Ground Operations
Common mistakes
Using a carburetor-style start on a hot fuel-injected engine.
It floods or vapor-locks the engine and overheats the starter.
Instead: Learn the POH hot-start procedure for that airplane.
Calling "Clear!" without looking.
People near the propeller may be outside your quick glance.
Instead: Look all around, call, and wait before engaging the starter.
Ignoring a weak battery after a ground-power start.
It may mean a charging-system fault.
Instead: Watch the ammeter after start and have it checked if charging is abnormal.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice engine starting out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Airplane Flying Handbook (FAA-H-8083-3C): Ground Operations; Transition to Complex Airplanes
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C)
- Risk Management Handbook (FAA-H-8083-2A)
- Commercial Pilot ACS (FAA-S-ACS-7B): Area II
- Your airplane's POH/AFM: normal procedures and checklists
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.