Fam 2 Flashcards
Np, Nr, torque oddities
If you see any fluctuations in Np, Nr, or torque treat it with EMIF
Single engine conditions establish
Level wings, check airspeed (accel or deccel to bucket speed ~ 70 kias)
Check IVISI…. can you maintain level flight???
What causes a compressor stall?
Aerodynamic disturbance of smooth airflow pattern through the engine
Compressor stall indications
Spiking TGT, hang-up or drop in Ng, loss of power, noises (like banging)
**inverse relationship between TGT and Torque (high high TGT because air is not flowing through for cooling or to produce engine power to produce torque)
**Inverse relationship between TGT and Ng (high temp because no air to cool and low Ng because no air to turn turbines)
Compressor stall
- Emif - perform
- Pcl (malfunctioning engine) - idle
Note: if the Ng decay re-light feature attempts to relight the engine, subsequent compressor stalls may occur and damage to the engine. A yaw kick may be experienced each time the engine relights. The engine must be manually shutdown
Spiking/fluctuations (torque or TGT) can be the result of
Engine electronic circuitry or component failures
Spiking is
Instantaneous increase of an engine instrument
Fluctuations may be indicative
Of contaminated fuel
What may be an indication before power loss
Audible power surges with engine q/tgt spiking/fluctuations
Indications of an impending high-speed shaft failure include
Medium to high frequency vibrations
Or a “howl” accompanying thr vibration
LDS malfunction
Connection to HMU
Check during first takeoff: malfunction if torque are split
In stable hover: malfunction if torque are matched
Also in start up checklist
LDS malfunction warning
During low power or autorotative descents with an engine LDS malfunction, Np/Nr may rise rapidly and activate Np overspend protection (120%)
Engine air restart may be attempted any time after shutdown if
No indication of mechanical malfunction or engine fire potential
Meaning if engine failure accompanied by an explosion or unusual noise indicates damage to the engine. There is a possibility that any attempt to restart the engine may result in a fire. Under such circumstances, do not try to restart the engine unless it is needed to maintain level fligjt
How much altitude is required approximately for a dual engine restart
Approximately 5000 ft
In the event of an alternator failure, (engine air restart note)
The Ng signal may be unavailable (because the sensor is mounted on the alternator).
Engine start will not be possible without AC power to provide power to ignition exciter
