UPDATED ACTUAL Questions and
CORRECT Answers
Main advantage of axial flow compressor compared to centrifugal? - CORRECT
ANSWER - Smaller frontal area of compressor.
What section extracts energy from expanding gases in a turbine engine? - CORRECT
ANSWER - Turbine section
Part of the compressor that convert airflow into pressure for combustion? - CORRECT
ANSWER - Diffuser
2 primary gauges observed during gas turbine start - CORRECT ANSWER - High
pressure compressor (N1 TURB % RPM ) and internal turbine temperature (ITT)
What is the relationship between the airflow of cold air through the fan vs the hot air through the
turbine? - CORRECT ANSWER - Engine Pressure Ratio
Define EPR (Engine Pressure Ratio) - CORRECT ANSWER - Ratio of turbine discharge
pressure to compressor inlet pressure.
Compressor Stall cause? - CORRECT ANSWER - Excessive angle of attack on
compressor blades.
How to identify a compressor Stall? - CORRECT ANSWER - Loud bangs, lower N1 or
torque, higher EGT or ITT, engine surging
Purpose of a compressor bleed valve - CORRECT ANSWER - Reduce chance of a
compressor stall.
, Stationary blades between each rotor to direct airflow properly? - CORRECT ANSWER -
Stators
Hung start? - CORRECT ANSWER - Noramll light up but RPM does not increase to
normal idle
Hot start - CORRECT ANSWER - ITT exceeds max allowable.
When air is diverted from the compressor for service functions what happens? - CORRECT
ANSWER - Thrust decreases, ITT increases.
How do Cascade reversers work? And what engines are they found on? - CORRECT
ANSWER - Blocker doors seal off fan cold airflow exit and a sleeve moves to expose the
cascade; Turbofan
Blocker door reversers are found on what engines? How do they work? - CORRECT
ANSWER - Turbofan. Blocker doors redirect cold airflow from fan at 45°
Clamshell reversers are found on ________ engines and work by __________? - CORRECT
ANSWER - Turbojet engines or small turbofan; redirects cold airflow at the rear of the
engine 90°
What's the difference between bucket/target reversers and clamshell? - CORRECT
ANSWER - Targets deflect hot air. Clamshells cold.
In the BETA range what does the power lever control? - CORRECT ANSWER - Blade
angle and fuel flow. RPM increases by retarding the lever.
What is a "FREE TURBINE" - CORRECT ANSWER - Two seperate shafts. compressor
and propellor