Asymmetric Flight

Question 1

Combined Effects of Asymmetric Flight

Answer 1

Initially the a/c will yaw towards the dead engine. However, due to the loss of airflow and increased drag from the dead engine, it will then roll and pitch down towards the dead engine due to the loss of lift from the dead wing.

Overall, if it is left to do its own thing then it will descend into a increasingly steep spiral dive.

Question 2

Standard Control Recovery

Answer 2

RUDDER - Prevent the yaw, maintain constant direction, step on the ball

AILERON - Level the wings

PITCH ATTITUDE - Adjust to maintain speed

Question 3

Critical Speed Vmc

Answer 3

As speed decreases the rudder required to prevent the yaw increases. When the rudder reaches its full extent, control can be limited if the speed continues to decay.

Question 4

The effect of power setting on critical speed

Answer 4

Varying power, varies the yaw. Therefore this varies how much rudder is required. Therefore this alters the speed at which the rudder reaches full deflection.

High power increases critical speed

Anything that effects the thrust of the operating engine will affect the critical speed. E.g altitude, as thrust decreases with altitude, the yaw also decreases with the same power setting. Which means an increase in altitude = a decrease in critical speed

Question 5

The effected of C of G on the critical speed

Answer 5

Yawing moments all act around the C of G.

Therefore the effect of the rudder will be dependant on the moment arm.

A rearward C of G will reduce the moment arm and therefore reduces the effectiveness of the rudder thus increasing the critical speed.

Question 6

How is VMCA gathered

Answer 6

Max 5* bank to the live engine 
Take off power
Unfavourable weight 
Aft most C of G 
Take off configuration 
Gear retracted 
Wind-milling prop
Not more than 150 ft/lbs of force required to maintain control 

VMCA is only a guide, the real VMC in an actual scenario would probably be higher.

Question 7

Take off Safety Speed (TOSS)

Answer 7

Speed at or above the pilot should be able to maintain control in the most critical situation should an engine fail.

Designed to give safe margin above the stall and VMCA
The greater of 1.1 x VMCA or 1.2 x stall speed

Question 8

Single Engine Safety Speed (VSSE)

Answer 8

Speed at or above which the pilot should be able to maintain control during airborne flight

82kts on the DA42

Question 9

Blue line on ASI

Answer 9

VYSE

Speed for the best rate of climb, single engine.

The speed for the best excess power

82kts on DA42