AMS 274 UNIT 4 EXAM QUESTIONS AND
ANSWERS GRADED A+ 2026
A typical Gear ratio for an air turbine starter is 25:1. If the turbine is rotating @ 80,000 RPM's,
what would the input RPM be to the gear box? - ANS 3,200 RPM
With a variable vane system when will the vanes be most closed? - ANS at Low RPM
What happens if the vanes are stuck in the open position? - ANS Engine will stall in low
power
A clicking noise heard from an air turbine starter on engine coast down is a result of what? -
ANS Pawls re-engaging and riding the ratchet in case we need a re-start
Which igniter plug requires special handling due to semi-conductor material? - ANS Low
voltage shunted surface gap (Self Ionizing)
What does the semi conductor material do when its HOT and COLD? - ANS Cold- Conducts
Hot- Isolates
What is autoignition and what does it sense? - ANS Ensures instantaneous igniton if an
engine loses power. Senses Torque, Oil Pressure, and loss of Compressure dischatge pressure
What positions are fail type anti-ice valves in? - ANS Powered closed and spring loaded open
@COPYRIGHT 2026/2027 ALLRIGHTS RESERVED 1
, What instrument indication would you most likely see when engine anti-ice is turned on? -
ANS Slight Rise in EGT (10 Degrees)
Starting sequence - ANS Starter, Ignition, Fuel
When do you disengage the starter? - ANS When it reaches self accelerating speed
Where is the Pressure Regulating and Shutoff valve located? - ANS Pneumatic starter Unit
What does the PRSV do? (Pressure Regulating, and Shutoff valve) - ANS controls airflow to
the pneumatic starter
What parameter is the most critical to observe? - ANS TIT
What indicates a successful start on a turbine engine? - ANS Rise in EGT
At what RPM is a stall most likely to occur? - ANS Low-Medium
When are the bleeds open? - ANS at Low power
What if the bleeds are open @ High power? - ANS High EGT is expected
What is the purpose of the bleed valve? - ANS Dumb unwanted air overboard to prevent a
stall
Performance Indicators - ANS EPR, Fan speed, Torque, Thrust
@COPYRIGHT 2026/2027 ALLRIGHTS RESERVED 2
ANSWERS GRADED A+ 2026
A typical Gear ratio for an air turbine starter is 25:1. If the turbine is rotating @ 80,000 RPM's,
what would the input RPM be to the gear box? - ANS 3,200 RPM
With a variable vane system when will the vanes be most closed? - ANS at Low RPM
What happens if the vanes are stuck in the open position? - ANS Engine will stall in low
power
A clicking noise heard from an air turbine starter on engine coast down is a result of what? -
ANS Pawls re-engaging and riding the ratchet in case we need a re-start
Which igniter plug requires special handling due to semi-conductor material? - ANS Low
voltage shunted surface gap (Self Ionizing)
What does the semi conductor material do when its HOT and COLD? - ANS Cold- Conducts
Hot- Isolates
What is autoignition and what does it sense? - ANS Ensures instantaneous igniton if an
engine loses power. Senses Torque, Oil Pressure, and loss of Compressure dischatge pressure
What positions are fail type anti-ice valves in? - ANS Powered closed and spring loaded open
@COPYRIGHT 2026/2027 ALLRIGHTS RESERVED 1
, What instrument indication would you most likely see when engine anti-ice is turned on? -
ANS Slight Rise in EGT (10 Degrees)
Starting sequence - ANS Starter, Ignition, Fuel
When do you disengage the starter? - ANS When it reaches self accelerating speed
Where is the Pressure Regulating and Shutoff valve located? - ANS Pneumatic starter Unit
What does the PRSV do? (Pressure Regulating, and Shutoff valve) - ANS controls airflow to
the pneumatic starter
What parameter is the most critical to observe? - ANS TIT
What indicates a successful start on a turbine engine? - ANS Rise in EGT
At what RPM is a stall most likely to occur? - ANS Low-Medium
When are the bleeds open? - ANS at Low power
What if the bleeds are open @ High power? - ANS High EGT is expected
What is the purpose of the bleed valve? - ANS Dumb unwanted air overboard to prevent a
stall
Performance Indicators - ANS EPR, Fan speed, Torque, Thrust
@COPYRIGHT 2026/2027 ALLRIGHTS RESERVED 2
