Powerplant & APU Flashcards
What is APR and what does it do?
Automatic Performance Reserve
If an engine fails during TO, the system will increase thrust 2% on the operating engine.
Above 79% N1, how is the engine speed controlled?
By thrust levers
Approximately what percentage of total thrust is produced by the air that passes through the N1 fan?
85%
Which ignition system must be used when starting with DC power? Why?
B - Because A is on the AC system and B is on the DC system.
How is oil cooled?
By the fuel/oil heat exchanger
What components are located on the accessory gear box of the engine?
- Engine lubrication pumps
- Integral drive AC generator (IDG)
- Air turbine starter
- Engine fuel control unit & pump
- Hydraulic pump
- Alternator that powers N1 control Amp.
What is the purpose of Variable Geometry (VG) vanes on the APU and engine compressor sections?
Improves efficiency of the compressor by changing the airflow angle of attack (AOA) at the compressor blades and protects compressor from stall & surge damage.
How is revers thrust actuated when the pilot lifts the thrust levers?
Air is ducted forward through cascade vanes by 14th stage bleed air that moves the engine cowl aft activating the reverse flow.
- How many fire detection loops are located around the engine?
- How many fire detection loops are located in the engine pylon?
- 2
2. 2
Are any fire extinguishers available to fight a fire in the jet pipe or engine pylon?
NO
Name five things that happen when an engine fire push switchlight is pressed?
- LH & RH squibs are armed.
- Fuel feed shutoff valve closes.
- Bleed air shutoff valve closes.
- Hydraulic shutoff valve closes.
- Engine driven generator is tripped.
What is the EGT limit for starting the APU?
743 degrees C
What is the maximum allowable altitude for bleed air extraction from the APU?
15,000’
Under which in-flight condition is APU bleed air extraction permitted for engine starting?
13,000’
What is the maximum allowable altitude for starting the APU?
30,000’
What is the main purpose of the APU?
To operate the 30kVa generator
What is the purpose of the APU LCV?
To provide bleed air to 10th stage on the main engines for engine starting.
Which malfunctions will cause the APU to automatically shut down?
- Fire
- Overspeed of 107%
- ECU failure
- DC power loss
- Loss of EGT signal
- Loss of RPM signal
- Over temperature of EGT
- High oil temperature
- Low oil pressure
- Overcurrent
What happens when the APU PWR/FUEL switch is pressed in?
- Performs a self test (APU in BITE)
- RPM & EGT gauges displayed on status page
- Opens APU intake door
- Opens APU fuel SOV
- Starts the cross flow/APU fuel pump
How can fuel be supplied to the APU if the XFLOW/APU pump is inoperative?
From the right engine fuel feed manifold via the APU negative gravity relief valve.
What is BITE?
Built in test equipment
What is the minimum battery voltage required to start the APU?
22 Volts
What cools the APU oil and APU enclosure?
Accessory gearbox fan provides oil cooling and ventilation of the enclosure.
- How many fire detection loops are around the APU?
2. How many fire extinguishers are available to fight an APU fire?
- 2
2. 1
