ATPL theory questions

[keith williams]

answers to new questions

Question 1.
In a fully powered flying control system the cockpit controls are connected to the pilot valves. The pilot valves control the flow of pressurised fluid to and from the actuators, thereby exerting very large control forces onto the control surfaces. These forces are so large that the aerodynamic loads cannot be fed back through the system. So there is no aerodynamic feedback, which means that servo tabs cannot be used. The term Servo Valve is just another name for the Pilot Valves. So taking the above into account the only correct answer is Servo Valves.

Question 2.
This one requires a bit of thought. If we enter ground effect at CONSTANT PITCH ATTITUDE the ground will reduce down wash, thereby increasing our ANGLE OF ATTACK. This will in increase cl thereby increasing lift. But the reduced down wash will decrease cdi thereby decreasing drag. But the question specifies CONSTANT ANGLE OF ATTACK. To achieve this we must push the nose down to decrease PITCH ANGLE such that we have CONSTANT ANGLE O F ATTACK. In this situation we we have no increase in Cl, but the reduced down wash will decease the cdi. Taking the above into account the only correct answer is induced drag decreases.

Question 3.
Any worthwhile book dealing with high speed flight will include diagrams showing the way CL and CD vary when accelerating through the transonic speed range. The diagram for CL will show that it increase at speeds just above Mcrit, it then decreases until increasing slightly just before Mcdr, before decreasing again. The overall effect is a decease, but the best option in this question is that CL varies with Mach Number.