Powerplant Flashcards
What device or part of the engine provides engine governing/control?
FADEC
If a FADEC 1A Fail caution light illuminates, does the engine quit or go into over speed?
No. Complete loss of a single FADEC channel will not degrade engine performance.
If a FADEC 1A and 1B caution light illuminated, would the engine continue to operate?
No- Loss of both FADEC Channels on a single engine will cause that engine to fail.
How is the FADEC powered?
Powered by the engine alternator as the primary source
Helicopter 28 vdc power is used as a backup source in case of alternator failure. Battery bus for Chan A and #1 DC Primary for Chan B
During a normal Cat A takeoff (5 minute limit) what limits are controlled by FADEC to protect the propulsion or drive system?
995ºC TGT
100 % TQ
102.9 % NG
In extreme flight situations, is it possible to get more power from the engine (exceed 5 minute power) during AEO
Engine and main gear box protection features are built into the FADEC to prevent the pilot from exceeding posted limits. These limits can be shifted upwards via the “blow away” logic when additional power is required in extreme flight situations. AEO- Tq 100% to 120%, NP/Nr 100 – 95% : TQ 120 -140, NP/NR 93- 88%
What is a Engine Power Assurance Check and when is it required?
- It confirms that published performance is assured.
- The power assurance check will be accomplished once each day.
- It can be completed on the ground or in flight
- If in flight, the airspeed must be stabilized above 80 KIAS
Explain the main engine starter system.
- A Pneumatic starter mounted on the accessory gear box of each engine.
- It uses pneumatic air from the APU, opposite engine if it is running, or an external source to power the starter.
- The pilot can select the bleed air source by use of the air source heat start switch
If attempting an air restart with the number 1 engine operating, the APU on and the Air source heat start switch in the Eng position, what provides the pneumatic air for engine restart?
- APU if the operating engine TQ is less than approximately 80%
- The operating engine if the operating engine TQ is approximately 80% TQ or greater
If a cross bleed start was used, would the start sequence cause the operating engine to lose available power?
Yes, use of engine cross bleed will result in a loss of up to 3% power of the operating engine.
Can a pilot start both engines simultaneously? Are there any limitations?
Both engines may be started simultaneously when the OAT is below 25C at sea level. Decrease allowable OAT 2C per thousand feet of altitude.
After engine start, are there any operating ranges that the pilot must avoid prolonged operation in?
NP/NR 36 to 49% (Tail rotor drive shaft critical range)
NP/NR 56 to 67% (Engine power turbine critical range)
During engine start, what action should be taken in the case of a hot start? Does FADEC provide hot start prevention in all start situations?
- With the engine throttle in idle during the start sequence- Hot start prevention is provided
- With the engine throttle in fly during the start sequence- Hot start prevention is not provided.
- Max TGT during engine start is 1000 C.
During cruise flight the engine oil temperature is 140C. Is any pilot action required?
132° to 149°C is a 15 minute limit
What are the starter limits?
Starter Motoring limits- 2 minutes on, 5 minutes off, 2 minutes on, 30 minutes off.
Temps below 15°C. 4 consecutive starts, 15 minute cooling, 4 consecutive starts, 30 minutes cooling
Temps above 15°C. 2 consecutive starts, 5 minute cooling, 2 consecutive starts, 30 minutes cooling
