Engine Starting

CA.II.C.S1 wants the airplane positioned considering structures, other aircraft, wind, and the safety of nearby persons and property. The AFH puts numbers to the hazard: propeller or engine thrust "can accelerate objects to substantial velocities," so the ramp around the airplane must be clear of persons, equipment, and hazards — and checking what is behind the airplane prior to engine start is standard practice (AFH ch. 2).

Before engaging the starter:

1. Anti-collision lights on (position lights too at night)
2. Brakes depressed
3. One hand on the throttle
4. "CLEAR" out the side window
5. Wait for a response

Two different failures. Holding the brakes prevents the airplane from rapidly lunging forward if the engine catches at a high power setting; keeping a hand on the throttle lets you manage the initial starting engine speed instead of discovering it. After start the throttle is set to the AFM/POH value — generally 1,000 rpm is recommended, which lets oil pressure rise while minimizing engine wear from insufficient lubrication at high rpm (AFH ch. 2).

Oil pressure should rise to at least the lower AFM/POH limit within 30 seconds in most conditions. If it doesn't reach and maintain the specified value within the required time, shut the engine down immediately — serious internal engine damage is otherwise likely (AFH ch. 2). This is a memory item, not a checklist lookup, because the whole window is 30 seconds.

Starters are electric motors not designed for continuous duty; excess heat buildup damages internal components and a prolonged or difficult start can drastically shorten service life. The AFH guidance: avoid continuous starter operation for periods longer than 30 seconds without a cool-down period of at least 30 seconds to 1 minute, and some AFM/POHs specify longer cool-down routines. The smell of burning insulation means the recommended cranking time has been exceeded. After repeated unsuccessful attempts, stop and get a qualified person to find the cause (AFH ch. 2).

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 action is immediate shutdown (AFH ch. 2) — a starter being driven by a running engine destroys itself and can damage the accessory case.

Follow the AFM/POH sequence for each — the point of knowing the three is recognizing which one you're in.

• Cold — fuel vaporizes poorly, so the engine needs priming per the POH; below and approaching freezing, service with the proper seasonal oil grade and apply engine preheat (AFH ch. 2).
• Hot — the residual heat has already vaporized fuel in the lines; priming a hot engine the way you'd prime a cold one is the standard route to flooding it.
• Flooded — too much fuel, so lean it out: the POH procedure is mixture to idle cutoff, throttle open, crank, then mixture rich and throttle back to idle as it fires.

The commercial-level habit is diagnosing before cranking rather than repeating the attempt that just failed.

The AFH names the whole sensory set: be attentive for sounds, vibrations, smells, or smoke that are not consistent with normal after-start operational experience, and any concern should lead to a shutdown and further investigation (AFH ch. 2). Add the instrument scan — oil pressure rising, ammeter charging rather than pegged, rpm stable and not surging.

Follow the AFM/POH exactly:

• Correct polarity and voltage
• The specified connection and disconnection order
• Avionics off through the process, to protect them from transients

Then ask the question that matters more than the start: why was the battery flat? A battery too weak to turn the engine is also a battery you cannot count on as an electrical reserve in flight. On a revenue or passenger-carrying flight that's a maintenance discussion before departure, not a note for later.

Throttle to idle first, and the chocks are approached only from the rear of the propeller — never from the front or the side. The AFH is unusually direct here: 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 (AFH ch. 2). Brief the route before start, not during.

Almost never, and you should say so before you describe technique. The AFH states plainly that hand propping is "a hazardous procedure when done perfectly," that the consequences of the hazards "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. It exists as a procedure because airplanes were manufactured without electric starters — not as a workaround for a dead battery on a Tuesday (AFH ch. 2).

Because the switch works by short-circuiting the magneto's primary circuit to ground. If the switch is faulty, it can be in the "off" position and still permit current to flow, which would allow the engine to start when the switch is off (AFH ch. 2). A broken P-lead produces exactly this condition, and it's silent — nothing in the cockpit tells you. Hence the rule: while touching a propeller, always assume the ignition is on.

• A team of two properly trained people, both familiar with the airplane and the technique. One directs and pulls the blades; one sits in the airplane to hold the brakes and work the controls as directed. A person unfamiliar with the controls should never occupy the pilot's seat.
• Firm footing — loose gravel, wet grass, grease, mud, oil, ice, or snow can slide the propper into the blades. If firm footing isn't available, relocate the airplane.
• Agreed voice commands before starting.
• Fuel system and engine controls set for a normal start, magneto switch confirmed OFF, and the descending blade positioned slightly above the horizontal.
• Stand slightly less than one arm's length from the blade, facing the descending blade squarely — too far away forces an unbalanced lean that can pitch you forward into the blades — with room to step away as the engine fires, which also safeguards against brake failure (AFH ch. 2).

Gripping the blade with the fingers, and failing to step back. The blade is swung by forcing it downward rapidly, pushing with the palms of both hands — if it's gripped tightly with the fingers, a misfire, kickback, or momentary reverse rotation can draw the person's body into the blades. As the blade is pushed down, step backward away from the propeller. And if the engine doesn't start, the propeller is not repositioned for another attempt until the magneto switch is verified OFF (AFH ch. 2).

Excessive throttle opening after the engine has fired is the principal cause. Gradual opening of the throttle while the engine is cold reduces the potential for backfiring; slow, smooth throttle movement assures correct engine operation. Once running, check oil pressure — if none shows within 30 seconds, stop the engine and find the trouble — then set warm-up rpm, usually between 1,000 and 1,300 rpm (AFH ch. 2).

Most reciprocating engines are air-cooled and depend on forward speed for cooling, so ground running is where cylinders overheat. During all ground running, maintain:

• Propeller in full low pitch
• Airplane headed into the wind
• Cowling installed
• Engine instruments monitored closely
• Cowl flaps open — do not close them for warm-up

Also make sure personnel, damageable ground equipment, and other aircraft are clear of the propeller wash (AFH ch. 2).