Multi Engine Aerodynamics

Question 1

What determines if an engine is critical?

Answer 1

P
A
S
T

Question 2

What are the drag factors when in OEI?

Answer 2

Full Flaps - 400 FPM
Windmilling prop - 400 FPM
Gear Extended - 150 FPM

Question 3

What are the Four warning signs that Vmc is occurring or about to occur?

Answer 3

1. Loss of directional control - the rudder pedal is depressed to its fullest travel and the airplane is still turning towards the inoperative engine
2. Stall warning horn - could result in a spin
3. Buffeting before the stall - same reason as the stall warning horn
4. A rapid decay of control effectiveness - any loss of control effectiveness could result in a loss of control of the aircraft

Question 4

To recover from Vmc, what two actions must occur simultaneously?

Answer 4

1. Reduce power on the operating engine - this will reduce the asymmetrical thrust causing the Vmc in the first place
2. Pitch down - lowering the nose of the airplane will increase the forward airspeed making the rudder more effective in regaining and maintaining directional control

Question 5

As density altitude ____, Vmc speed will ____. Why?

Answer 5

increases, decrease. Because less engine power at higher density altitude = less asymmetric thrust = less yaw towards dead engine = lower Vmc