How do pitch, roll, and yaw forces change during an engine failure?
Pitch decreases, roll is induced toward the failed engine, and yaw is generated toward the dead engine.
Which axis usually gives the most obvious indication of an engine failure?
Yaw.
Why does lift change on one wing during an engine failure?
From a reduction in accelerated slipstream caused by the loss of thrust in that engine.
How would aerodynamic forces be different if an engine failure occurred on the ground?
The roll moment would not be felt as strongly because the wheels are on the ground and less lift is being generated.
Why must pilots practice movements to compensate for aerodynamic forces during an engine failure?
Because when a real engine failure occurs, the response needs to be prompt and correct.
Why does a 50% reduction in power cause a far greater reduction in performance?
Because performance is a by-product of excess thrust. An engine failure both reduces thrust and adds drag.
How can performance be improved following an engine failure?
Reduce drag by establishing zero sideslip and changing configuration as appropriate.
What distinguishes sideslip from zero sideslip?
In sideslip, rudder and aileron maintain heading and wings level; in zero sideslip, bank slightly toward the operating engine and relax rudder slightly (split the ball).
How might planning differ for engine failure after takeoff at sea level vs. high density altitude?
At high density altitude, the airplane may not climb or maintain level flight on one engine. Consider an off-airport landing and waiting for better conditions.
What actions can increase single-engine performance before departure?
Reduce weight, maximize power, and use a short-field takeoff configuration.
What aerodynamic force defines VMC?
Rudder force — when yaw from engine failure exceeds rudder authority, VMC is reached.
Why is VMC important during takeoff?
Below VMC after an engine failure, recovery is likely impossible without altitude.
What criteria establish VMC?
Critical engine inoperative/windmilling, operating engine max power, unfavorable weight/CG, 5° bank, ±20° heading, takeoff config, sea level, out of ground effect, gear up, 150 lbs rudder force.
Why is VMC determined with gear up?
Landing gear stabilizes yaw (keel effect) and lowers VMC; with gear up, VMC is higher and more critical.
How does density altitude affect VMC and performance?
Higher DA lowers VMC (less power) but also reduces performance.
What four factors make an engine critical?
P-factor, accelerated slipstream, spiraling slipstream, and torque.
How does P-factor affect the critical engine?
The descending blade’s thrust arm is longer on the right engine, making the left engine critical.
How does accelerated slipstream affect the critical engine?
Greater lift behind the descending blade is farther from CG on the right side, so left engine failure causes more asymmetry.
How does spiraling slipstream affect the critical engine?
Right engine’s slipstream misses the tail, while the left’s hits it — making the left critical.
How does torque affect the critical engine?
Torque adds a left-turning tendency; failure of the left engine makes it worse.
Do counter-rotating engines have a critical engine?
No. Counter-rotation cancels the asymmetries; both are equally critical.
Difference between single- and multi-engine propeller governors?
Multi-engine props fail to high pitch/low RPM (feather). Singles fail to low pitch/high RPM (windmill).
What does an unfeathering accumulator do?
Uses pressurized oil to move propeller out of feather for restart.
What is a propeller synchronizer/synchrophaser?
Automatically adjusts RPMs to reduce vibration and noise; pilots can match props manually using tachometer and sound.
