ATA 77 - Engine Indicating Flashcards
How is the Engine RPM indicator (Ng) power supplied? Does it sends its data anywhere?
By the 28 VDC battery bus
Yes, it sends its data to the FDR
How do the Engine RPM indicator (Ng) get its speed indication?
It receives and counts the frequency of the AC voltage from it’s related PMA.
(The Ng indicator changes this signal into an analogue signal which is
displayed as % Ng)
How do the torque indicator receive the torque signal?
It receives a torque signal from its related torque and overspeed sensor through the torque circuit in the ECU/DECU.
Which indicators is the only ones NOT supplied by the battery bus?
The fuel flow indicator and the Fuel used indicator
- Fuel flow indicator is powered by the +28 VDC LH/RH Main Bus)
- Fuel used indicator is powered by the +28 VDC RH Main Bus
What prevents fluctuating TRQ signals during start and feather mode?
The LH/RH Torque Signal Cutoff operated by the condition levers.
How do the Np indicator (in the cockpit) get its signals?
From the power turbine drive shaft speed sensor on the PGB drive shaft housing. This signal then goes through the DECU
Where is the ITT measured?
In front of the power turbine at T4.5
How is the ITT measurment improved?
By the 4.5 Trimmer mounted on the main frame. This is needed because it is not practicable to measure the gas stream temperature at T4.1
ITT:
1: When will ENGINE OV TEMP warning indicate?
2: How do you test the digital display?
3: Where do the indicator send its information further?
1: If the temperature exceeds 960°C
2: Test 1 panel - LAMPS test LWR position.
3: To the FDR
How is the Fuel Flow Transmitter powered?
It requires no electrical power due to it obtain its driving power from the fluids flowing through it
From where do the Fuel Flow indicators get input?
From its respective fuel flow transmitter
What are the three windings in the PMA doing?
- Ng signal for the cockpit indicator
- Sends power to the ignition exciter assembly
- Provides power to the DECU and the overspeed protection system
