Engine Starting

A passenger does what you tell them. A student is reaching for switches, and the two hazards you are managing are the propeller and the student's hands (AI.V.C.R1). The instructor's job before the key moves:

• Brief who touches what on this start. On a first lesson the student's hands may be in their lap; by pre-solo they run the whole checklist and you keep a hand near the throttle.
• Brief what you will do if it goes wrong — that you may take the throttle or the mixture without warning or discussion.
• Confirm the area is clear yourself, out your own window, regardless of what the student calls.

Teaching the start is a case where the demonstration must conform exactly to the explanation, because learners generally imitate the instructor's performance, including all safety procedures (AIH ch. 9).

From AFH ch. 2, in order:

1. Ramp clear of persons, equipment, and other hazards that could contact the airplane or propeller — and check what is behind the airplane as standard practice, because propeller or engine thrust can accelerate objects to substantial velocities, damaging property and injuring people on the ground.
2. Anti-collision lights ON at all times before engine start; position (navigation) lights on as well for night operations. Teach this as a signal to the ramp, not a checklist item.
3. "CLEAR" called out the side window just prior to starter engagement — and wait for a response from anyone nearby before engaging.
4. Brakes depressed and one hand on the throttle when activating the starter. Properly operating brakes engaged before starter engagement prevents the airplane from rapidly lunging forward; the hand on the throttle manages initial starting engine speed.
5. After start, set rpm per the AFM/POH — generally 1,000 rpm is recommended, to let oil pressure rise while minimizing engine wear from insufficient lubrication at high rpm.

Both have a clock running:

• Oil pressure: in most conditions it should rise to at least the lower AFM/POH limit within 30 seconds. If the limits are not reached and maintained, serious internal engine damage is likely — shut the engine down immediately (AFH ch. 2).
• Starter duty cycle: starters are electric motors not designed for continuous duty. Avoid continuous operation for periods longer than 30 seconds without a cool-down of at least 30 seconds to 1 minute — some AFM/POHs specify longer. The smell of burning insulation means the recommended cranking time has been exceeded.

The whole window on the first one is 30 seconds. A student who has to find the page will not make it.

• Calling "clear" as a word, not a check. The student says it while looking at the panel. Correction: make them point out the window as they call, and make them wait.
• Cranking through a failed start. Students repeat the attempt that just failed rather than diagnosing which start they're in. Correction: after an unsuccessful attempt, the student states the diagnosis (cold, hot, flooded) before touching the key again. After repeated unsuccessful attempts, the AFH says to seek advice from a qualified person to determine the cause (AFH ch. 2).
• Both hands on the key. No hand on the throttle means the engine picks its own rpm. Correction is physical: place their hand.
• Not looking at the oil pressure gauge at all. Correction: they call "oil pressure rising" out loud, every start, from lesson one — a habit pattern that costs nothing and catches everything.
• Missing the sensory picture. The AFH asks the pilot to be attentive for sounds, vibrations, smells, or smoke inconsistent with normal after-start experience, and any concern should lead to a shutdown and further investigation. Teach the student that "it sounded weird" is a complete and sufficient reason to shut down.

It's rare, but the indications are a continuous and very high current draw on the ammeter, and on some airplanes a dedicated starter-engaged warning light. The engine should be shut down immediately (AFH ch. 2). Teach it by pointing at the ammeter during the post-start scan every flight — a student who never looks there cannot recognize the abnormal.

The route, before start, not during. The AFH is blunt about why: the propeller is nearly invisible, and serious injuries and fatalities have occurred when people who had just started an engine walked or reached into the propeller arc to remove chocks, reach the cabin, or move toward the tail. The procedure is throttle to idle first, and the chocks approached only from the rear of the propeller — never from the front or the side (AFH ch. 2). For an instructor this is a briefing item on the very first flight, because a student who has never been told will walk the shortest line to the door.

Follow the AFM/POH exactly — correct polarity and voltage, the specified connection and disconnection sequence, and the AFM/POH's direction on avionics during the process. Then ask the instructor question that outranks the procedure: why was the battery flat? A battery too weak to turn the engine is a battery you cannot count on as an electrical reserve, and with a student aboard you have just accepted a single-point failure into a training flight. Teaching-wise, this is a good moment to let the student reach the airworthiness conclusion themselves: the PIC determines whether the aircraft is in condition for safe flight (91.7(b)).

Specific procedures come from the approved engine start checklist in the AFM/POH (AFH ch. 2); the instructor value is in teaching the student to identify which situation they're in first.

• Cold: fuel vaporizes poorly, so the engine needs priming per the POH. When temperatures approach and descend below freezing, service the engine with the proper grade of oil for the seasonal conditions and apply engine preheat (AFH ch. 2).
• Hot: residual heat has already vaporized fuel in the lines. Priming a hot engine like a cold one is the standard route to flooding it.
• Flooded: too much fuel; the POH procedure leans it out.

The transferable skill isn't the three procedures, it's the diagnostic pause before the second attempt.

You are not the only person with hands. Specific mitigations:

• Positive control of the switches. State who is starting this engine before anyone touches anything — the same principle as positive exchange of flight controls, applied on the ground.
• Your hand near the throttle and mixture, always, regardless of who is running the checklist. If the engine catches at high power, your intervention window is under a second.
• Watch the ramp, not the student. They're looking at the panel; someone has to be looking outside.
• Set the shutdown criteria out loud before starting — no oil pressure in 30 seconds, abnormal sound, ammeter pegged — so that a shutdown is a pre-made decision rather than an argument.

Say no, and say why before you describe anything. The AFH states that hand propping is a hazardous procedure when done perfectly, that the consequences of the hazards associated with hand propping are serious to fatal, and that persons not trained, not competent, or who do not understand how to mitigate the hazards should never perform this procedure. Its stated reason for existing is historical: most airplanes today are equipped with electric starters, and the starter should be working if the airplane is airworthy — if not, a certificated Aviation Maintenance Technician should be called to make the repair (AFH ch. 2). Vintage airplanes manufactured without electric starters are the actual use case. A student pilot is never one of the two trained people.

Because the switch can lie, and nothing in the flight deck tells you. The AFH states the rule directly: while touching a propeller, always assume that the ignition is on. Magneto switches work by short-circuiting the current to turn the ignition off; if the switch is faulty, it can be in the "off" position and still permit current to flow in the magneto primary circuit, which could allow the engine to start with the switch off (AFH ch. 2). Teach it as an absolute with no exception clause — the moment a student learns a condition under which the propeller is safe, the rule is gone.

• A team of two properly trained people, both familiar with the airplane and the technique. One directs the procedure and pulls the blades; the second sits in the airplane to ensure brakes are set and exercise controls as directed. A person unfamiliar with the controls should never occupy the pilot's seat.
• Stable ground free of debris. Loose gravel, wet grass, grease, mud, oil, ice, or snow might cause the person pulling the propeller to slip into the rotating blades. Unless firm footing is available, relocate the airplane.
• Both participants discuss the procedure and agree on voice commands and expected actions beforehand.
• Fuel system and engine controls set for normal start, magneto switch checked OFF, and the descending blade rotated to a position slightly above the horizontal.
• The person propping faces the descending blade squarely and stands slightly less than one arm's length from it. A stance too far away requires leaning forward in an unbalanced condition, which may cause the person to fall forward into the rotating blades when the engine starts. Leaving space to step away also safeguards against brake failure (AFH ch. 2).

Gripping with the fingers and failing to step back (AFH ch. 2). Both are body-position errors, which is why neither one can be taught from the right seat with words.

What makes this an instructor problem rather than a pilot problem: on a hand-prop you are almost never the person at the blade. You are at the controls, or you are the one who briefed whoever is. So teach it as a two-person procedure with assigned roles, and demonstrate the grip on a stopped propeller before anyone touches a live one.

• Palms, not fingers. The blade is forced downward rapidly, pushing with the palms of both hands. A finger grip means a misfire, kickback, or momentary reverse rotation can draw the person's body into the blades. Have the student show you the palm position and hold it while you look.
• The step back is part of the swing, not a separate action. Coach it as one motion — push down, step away — because a student who treats them as two steps completes the first and forgets the second.
• The reposition rule is the one to make absolute: if the engine doesn't start, the propeller is not repositioned for another attempt until it is verified that the magneto switch is turned OFF.

Your intervention criterion is simple and you should say it in the brief: if the grip or the footing is wrong, you call "stop" before the swing, every time. There is no correcting this one after the fact. And if you are not satisfied with the person at the blade, the airplane does not get started — declining is the instructor's call to make.

Excessive throttle opening after the engine has fired is the principal cause of backfiring during starting. Gradual opening of the throttle while the engine is cold reduces the potential for it, and slow, smooth throttle movement assures correct engine operation. Immediately after the engine starts, check oil pressure — if it does not show within 30 seconds, stop the engine and determine the trouble. If oil pressure is indicated, set the manufacturer's specified warm-up rpm, usually between 1,000 and 1,300 rpm (AFH ch. 2).

Because most aircraft reciprocating engines are air-cooled and depend on the forward speed of the aircraft to maintain proper cooling — and a ground lesson is, by definition, zero forward speed. During all ground running (AFH ch. 2):

• Propeller in full low pitch
• Airplane headed into the wind, cowling installed
• Cowl flaps open — do not close them for engine warm-up
• Engine instruments monitored closely at all times
• Personnel, damageable ground equipment, and other aircraft clear of the propeller wash

The instructor trap is a long post-start briefing at idle on a hot ramp while the student asks a good question. Answer it with the airplane pointed into the wind, or answer it after shutdown.