Propeller System

Question 1

What force moves the prop blade from feather to fine and reverse?

Answer 1

Oil pressure

Question 2

You are in cruise with both props set at 76% Np. After a few minutes you notice the right Np has increased to aprox 81%, you check the friction lock and it is tight. What has probably happened?

Answer 2

The primary governor has failed and the NF governor is protecting the engine against a power turbine overspeed by limiting fuel flow.

Question 3

What is the setting of the overspeed governor?

Answer 3

101.5%

Question 4

If the beta range light is flashing during the approach, reverse is not recommended on landing because:

Answer 4

The propeller may not come out of reverse

Question 5

In cruise a beta range light comes on steady and the associated engine Tq i s increasing. What is happening?

Answer 5

A malfunction in the beta backup system is causing the propeller to feather

Question 6

What force causes the propeller to increase pitch towards feather?

Answer 6

Counter weights and springs

Question 7

Just after take-off your primary governor has failed and propeller starts to overspeed. What governor will activate next and and at what % Np will it activate?

Answer 7

Overspeed governor at 101.5% Np

Question 8

During a max power climb (96% Np) you hear propellers quickly go out of sync, the aircraft yaws, and the engine slowly winds down to Min flow with the prop at 103% Np. What has happened?

Answer 8

The primary and overspeed governors have failed and the Nf governor is limiting fuel to the gas generator, reducing Ng, thus trying to control Np