Free CPL Aircraft General Knowledge Questions and Answers

Question 1

The valves in a four-stroke engine open and close:

Accepted Answer

none of these

Answer

Explanation:
The exhaust closes around 15° after TDC.
The exhaust opens around 55° before BDC.
The inlet opens around 15° before TDC.
The inlet closes around 60° after BDC.

Question 2

Detonation in AVGAS is reduced by fuel companies adding certain compounds. Fuel then has an octane rating. Typical blue AVGAS is approximately:

Accepted Answer

100

Answer

Explanation:
The main difference between 100LL (100 octane) and 100/130 relates to the minimum octane rating prescribed and different fuel mixtures (100 lean and 130 rich). This is the most simple explanation as to why they need different colors. Blue will always be 100LL, whereas 100/130 is green.

Question 3

When fuel enters the combustion chamber from the carby it is:

Accepted Answer

flowing in as a gas

Answer

Explanation:
The fuel has been vaporized by fast-moving air and is suspended in the air as a gas.

Question 4

During a glide descent carb heat should be applied in the following manner.

Accepted Answer

Applied prior to commencing glide and removed just prior to re-applying power

Answer

Explanation:
When it comes to carb ice prevention is better than cure. Applying carb heat before closing the throttle helps prevent formation. Removing before re-application of power ensures when you apply power, you have full power available. As we know from our carb heat test during our run-ups, we are 100-150 rpm lower with carb heat applied.

Question 5

The strength or power that acts on a piston during the power stroke is dependent on:

Accepted Answer

the air and fuel intake and the temperature it reaches after ignition

Answer

Explanation:
This question sounds confusing at first but think about the orientation of the engine in the engine bay. The fuel/air mixture from the carburetor enters the engine at the top. This means that the piston will move down first (to draw in the fuel) then up (to compress the mixture), down (to get the power after ignition), and up again for the exhaust stroke.

(CPL) Commercial Pilot Licence Practice Test

(CPL) Commercial Pilot Licence Practice Test

Free CPL Aircraft General Knowledge Questions and Answers