ATPL theory questions

[keith williams]

The increase in load factor caused by flying at different speeds in the same gust can be calculated using the following equation:

N increase at new speed = N increase at old speed x (V new / V old)

For the first question comparing the conditions at 1.9 VS and at 2.0 VS gives the following:

N increase at old speed = 2.9 - 1 (straight and level) = 1.9
Old speed = 1.9 VS
New speed = 2.0 VS

N increase at new speed = 1.9 x (2 / 1.9) = 2.0

Adding this increase to the initial straight and level load factor of 1 give a new load factor of 3.0



Using the same equation in the second question gives us the following:

N increase at new speed = 1.5 x (2 / 1.5) = 2

Adding this to the initial straight and level load factor of 1 g give new load factor = 3.0.


But option d in each question poses the possibility that the aircraft may stall before it attains these increased load factors, so we need to test this possibility.

We can do this using the following equation:

VS at new N = VS at old N x (square root of new N / square root of old N)


Inserting the data for question 1 gives the following:

VS at 2.9 g = VS at 1 g x (square root of 2.9 / square root of 1)

VS at 2.9 g = 1.7 VS at 1 g

The aircraft was initially flying at 1.9 VS, so it would not stall before attaining 2.9 g. So option d is incorrect.



Inserting the data for question 2 gives the following:

VS at 2.5 g = VS at 1 g x (square root of 2.5 / square root of 1)

VS at 2.5 g = 1.58 VS at 1 g

This means that the stalling speed at 2.5 g would be 1.58VS. But the aircraft is flying at only 1.5 VS, so it would have stalled before attaining 2.5 g. This means that the higher load factor of 3.33 g could not be attained. So option d is correct.