Engine Failure and Restart in Flight

An engine failure in flight is two steps followed by one decision: is there enough height to try a restart, or is this now a landing? The restart drill that follows is long, and it has an altitude ceiling and a two-minute clock attached to it.

At a glance

• Engine failure, step 1Airspeed 88 KIAS
• Engine failure, step 2Flaps UP
• Restart ceiling, immediate16,400 ft pressure altitude
• Restart ceiling, immediate (MÄM 40-838 or later)15,000 ft pressure altitude
• Restart ceiling, within two minutes10,000 ft pressure altitude

The failure itself

Engine failure in flight

1. Airspeed — 88 KIAS

2. Flaps — UP

Then comes the decision, and it turns on height: enough of it left to try a relight, and you try; too little, and the aeroplane is landed.

What the propeller tells you

NOTE — Short of a major mechanical defect, the propeller keeps turning in the airflow after the engine quits. One that has come to rest is evidence of exactly such a defect, and no starter-assisted relight is to be contemplated.

That is the single most useful observation in the drill. A turning propeller means the restart is worth attempting; a stationary one means it is not, and the time is better spent on the landing.

The restart window

Relight the engine at once and the ceiling is 16,400 ft pressure altitude — 15,000 ft on an airframe running the engine software of MÄM 40-838 or anything later approved. Take as long as two minutes over it and the ceiling drops to 10,000 ft.

NOTE — Let more than two minutes of cooling pass and the restart may simply not succeed.

Restarting the engine in flight

The restart drill

1. Airspeed — 88 KIAS

2. POWER lever — IDLE

3. VOTER switch — swap between ECU A and B. If either setting restores normal operation, maintain it and land as soon as possible

4. VOTER switch — back to AUTO, to retain ECU redundancy

5. Fuel valve — check NORMAL

6. Alternate air — as required

7. Fuel quantity — check

8. Fuel transfer pump — as required

9. ELECTRIC MASTER — check ON

10. ENGINE MASTER — check ON

If the engine does not start, the fuel valve is set to EMERGENCY. If it still does not start, the glide configuration is adopted — flaps UP — and an emergency landing carried out. The AVIONIC MASTER is then set ON if required.

CAUTION — Reach for a relight after an engine fire only where a safe emergency landing looks unlikely — and expect the attempt to fail, because a fire leaves the engine unable to restart.

Check yourself

• What are the two steps of the engine failure drill, and what decision follows them?

• What does a stopped propeller tell you, and what does it rule out?

• What are the three restart altitude limits and the conditions attached to each?

• What happens if the engine has been cooling for more than two minutes?

• Under what circumstances would you attempt a restart after an engine fire?

Study aid — always fly your aircraft's current AFM/POH.