Multi Engine questions

[siwi05]

Hello,

I have a Multi-engine exam coming up and have come across a few questions that I have not understood and have become stuck. These are from an unknown test prep question bank I received (Answers were not included :confused:).

If anyone could give some insight it would be much appreciated. Thanks :ok::ok:

1.) "If an engine failure occurs and the aircraft is banked towards the operating engine without any rudder application, the resultant of the operating engine thrust force and the horizontal component of lift will cause__"

A. A slip towards the operating engine
B. A descent and turn towards the operating engine
C. A climb and turn towards the failed engine
D. A slip towards the failed engine

For me, I could not decide between A and D. From my understanding the correct response to this scenario is to apply rudder force WITH bank (2-3deg). Since the rudder part was missing, I am not sure of what the reaction and result would be (same for question 2 A,B).

2.) "To maintain a strait and level flight after an engine failure by not using rudder, the airplane__"

A. Slip towards the operative engine
B. Slip towards the inoperative engine
C. No change at all
D. Slip will be centered

3.) "What is the absolute service ceiling?"

A. The density altitude where Vx and Vy are decrease
B. The maximum density altitude the airplane is capable of attaining or maintaining
C. Which use of best rate of climb
D. The pressure altitude where Vx and Vy are equal

4.)"Absolute service ceiling"

A. Pressure altitude when Vx and Vy are equal
B. Density altitude when Vx and Vy are decrease
C. Max. density altitude the aircraft is capable of attaining or maintaining
D. Which use of best rate if climb

[B2N2]

1. D The airplane yaws to the dead engine, you apply juts enough aileron to maintain wings level the nose is still pointing towards the dead side.

Here is some good reading: 17 Multi-Engine Flying (http://www.av8n.com/how/htm/multi.html)

2. B

3. B Absolute mean rate of climb is zero

4. C


These are two of the same questions.
Don't use Wiki to study but it's not a bad article:
Minimum control speeds - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Minimum_control_speeds)

[keith williams]

Questions 3 and 4 are defective because the Absolute Ceiling and the Service Ceiling are two different things.

RATE OF CLIMB
Best attainable rate of climb is equal to excess power divided by weight. Excess power is equal to power available minus power required. As altitude increases, the power available decreases and the power required increases. This means that as altitude increases, both the excess power and the maximum available rate of climb gradually decrease.

The Service Ceiling is the altitude at which the best attainable rate of climb has decreased to certain specified values. These values are 100 ft/min for propeller aircraft and 500 ft/min for jet aircraft.

If the aircraft continues to climb above the service ceiling the power available, excess power and best rate of climb all continue to decrease. The absolute ceiling is the altitude at which power available is just equal to power required. At this altitude, the excess power and rate of climb are both zero.

Both power available and power required vary in proportion to a number of factors including weight, load factor, altitude and airspeed. For all powered aircraft there is a speed at which the excess power and hence rate of climb are a maximum. This speed is called VY.

ANGLE OF CLIMB
The angle of climb of an aircraft is proportional to the excess thrust divided by the weight. Excess thrust is equal to thrust available minus drag. As altitude increases, the thrusts available decreases. This means that as altitude increases, both the excess thrust and the best angle of climb decrease. At the absolute ceiling the thrust available is just equal to the drag and so the excess thrust and the best angle of climb are both zero.

As airspeed changes, both the excess thrust and maximum climb angle change. The maximum climb angle at any given weight therefore depends upon the airspeed. The term VX refers to the calibrated airspeed at which an aircraft can achieve the greatest angle of climb.

At the absolute ceiling the thrust available curve is tangential to the drag curve. This means that there is just one airspeed (VX) at which there is sufficient thrust to maintain altitude and airspeed. At any other airspeed the aircraft will have insufficient thrust to maintain altitude, so it will descend. At this altitude the power available curve is tangential to the power required curve. This means that there is just one airspeed (VY) at which there is sufficient power available to maintain airspeed and altitude. At any other airspeed the aircraft will have insufficient power to maintain altitude, so it will descend. Both of these conditions occur simultaneously, so at the absolute ceiling VX is equal to VY and the best angle of climb and best rate of climb are both zero.

[siwi05]

@B2N2 Thank you for the input, very helpful article :)

@keith williams Thank you for the theory, getting a better sense of it now :)

Cheers.

[appleACE]

I haven't started my multi engined training yet, but I've looked ahead at the theory.

According to that you would not maintain wings level, instead you would bank towards the operating engine so that the horizontal component of the lift counteracts the asymmetric thrust without need for rudder input. This is of course after you have the aircraft stablised, not immediately on failure. Then you would have no sideslip but you instruments would indicate that you have a slip towards the operating engine.

I don't know what the answer to OP's question would be though, since the horizontal component would only cause an indication of slip, not actual slip.