Engines, APU Flashcards
What are the primary differences between an automatic and a manual start?
The automatic start sequence is under the full authority of the FADEC, which controls the start valve, igniters, and the fuel HP valves.
In the manual start sequence, the FADEC has limited control such that automatic start interruption and auto-crank are not available. Therefore, the Flight Crew must monitor engine
acceleration
When would you use a manual start?
MANUAL STARTINGD
A manual start is recommended if an automatic start is not successful due to any of the following:
• Engine Stall
• EGT overlimit
• Low start air pressure
A manual engine start is also recommended when an automatic start abort is expected due to the following:
• Degraded bleed performance or reduced EGT margins due to hot conditions or high altitude airport
• Marginal pneumatic source
• (A320) Intermittent ECAM ENG 1(2) IGN A(B) FAULT alert during the first start of the day
What controls the engines in all operating regimes?
Full Authority Digital Engine Control (FADEC) system
What functions does the FADEC control?
FADEC uses the following functions to control the engine and start parameters. These functions are outlined as follows:
Control of gas generator
Protection against engine exceeding limits
Power management
Automatic engine starting sequence
Manual engine starting sequence
Thrust reverser control
Fuel recirculation control
Transmission of engine parameters and engine monitoring information to Flight Deck indicators
Describe the redundancy of the FADEC.
The FADEC system has two-channel redundancy, with one channel active and one in standby. If one channel fails, the other automatically takes control.
What is the power source for the FADEC?
It has a magnetic alternator that provides an internal
power source. If this alternator fails, the FADEC automatically switches to the aircraft electrical power.
If the FADEC detects a fault during automatic start, is any crew intervention required?
No, The fault will be displayed on ECAM
When does the Idle Control function of the FADEC system regulate idle speed?
The FADEC uses IDLE CONTROL to regulate engine idle speed according to the following three modes (Modulated, Approach and Reverse) and conditions.
- Modulated idle for bleed system demand always on the ground unless reverse is selected and inflight when FLAPS lever at zero position
- Approach idle mode the idle is regulated according to aircraft altitude and allows the engine to accelerate rapidly from idle to go around thrust. It is selected in flight when the flaps are extended.
- Reveres idle is lightly higher than forward idle thrust and is selected on the ground when the thrust lever is in REV IDLE.
When will the FADEC abort a start?
If the FADEC detects a hot start, a hung start, a stall, no light up, a low start air pressure, a starter time exceeded, or thrust lever not at idle.
How is the IDG cooled?
The Integrated Drive Generator (IDG) fuel/oil heat exchanger cools the IDG oil.
How many igniters fire on an in-flight start attempt?
Both A and B igniters
How many igniters fire during a manual start?
Both A and B igniters.
When does continuous ignition automatically operate?
When an engine flameout is detected, it senses an EIU failure, or if there is an ignition delay during engine starting.
What is the active range of the A/THR?
From Idle to the CL detent. When one engine is operating, the active range is from Idle to the MCT detent.
What determines the maximum thrust the A/THR system will be able to command?
Thrust Lever Position
