One Engine Inoperative — Recognition and Control

An engine failure on a twin is a control problem before it is a performance problem. This lesson covers how you identify which engine has failed, how you hold the aeroplane straight, and what the manual is honest about regarding climb performance afterwards.

At a glance

• V_MCA (flaps UP)76 KIAS
• V_MCA (flaps APP)73 KIAS
• V_YSE85 KIAS
• Zero sideslip ballapprox. half a ball toward the good engine
• Zero sideslip bank3° to 5°
• Max power on the remaining engine, in flight92 % load or 2100 RPM
• Critical engineleft-hand, pilot's view

What one engine inoperative feels like

One engine inoperative means an asymmetric loss of thrust. With the controls coordinated it produces uncommanded yaw and roll towards the dead engine. Directional control is maintained mainly with rudder, supported by aileron.

The identifying mnemonic is dead foot, dead engine. Whichever foot is doing the work is standing on the side that still has thrust; the foot that meets no resistance is on the side that has failed.

NOTE — Look at handling and at performance, and on this type it is the left engine — left as the pilot sees it — that counts as critical.

Abnormal engine behaviour

First response

1. Full power — apply.

If the abnormal behaviour is sustained, go to the one engine inoperative procedures.

Holding it straight: minimum sideslip

With one engine inoperative, establish a minimum or zero sideslip condition — approximately half a ball towards the good engine, with 3° to 5° of bank. Wings level and ball centred is not the efficient configuration on a twin.

Engine failure during initial climb

WARNING — A climb is flown with the power well up, which makes the region under V_MCA — that is, under 76 KIAS with flaps UP, or 73 KIAS with flaps APP — a dangerous place to be. An engine quitting there can cost you control of the aeroplane. Cutting the thrust asymmetry to get the nose back under control becomes the first priority.

Engine failure during initial climb

1. Rudder — maintain directional control.

2. Airspeed — V_YSE 85 KIAS; keep it clear of V_MCA, which is 76 KIAS with flaps UP and 73 KIAS with flaps APP.

3. Operative engine — increase power as required, once directional control is established.

4. Inoperative engine — secure according to the engine securing procedure.

The order of steps 1 and 3 is the lesson. Directional control is established before power goes up, not after.

Engine failure during flight

Engine failure in the cruise

1. Rudder — maintain directional control.

2. Airspeed — as required, but never down to V_MCA: 76 KIAS with flaps UP, 73 KIAS with flaps APP.

3. Operative engine — increase power up to 92 % load or a maximum of 2100 RPM.

4. Inoperative engine — secure according to the engine securing procedure.

What the manual admits about performance

WARNING — Weight, configuration, the conditions of the day, speed and the handling of the pilot can combine such that the aeroplane will not climb at all on one engine — the rate goes negative. Whatever the combination, shoving the power on abruptly while one engine is out always makes the aeroplane harder to control.

Check yourself

• What does dead foot, dead engine mean in terms of which foot feels what?

• Which engine is the critical engine on this type?

• What ball position and bank angle define minimum sideslip, and towards which engine?

• In the initial climb procedure, does power on the good engine go up before or after directional control is established?

• What is the power limit on the remaining engine in the cruise procedure?

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