APU - Powerplant Flashcards
Max permissible load on the APU Generator?
40 KVA
Max altitude for starting?
37,000 ft
Max altitude for APU operation?
41,000 ft
Max altitude for APU bleed air extraction?
25,000 ft
Max speed with APU door open?
220 KIAS if APU not operating
No speed limitation if APU is operating
What battery voltage is required before starting the APU?
22 volts on both batteries
What does the main battery power during an APU start?
APU ECU
What does the APU battery power during an APU start?
Cranking of the 28 VDC start motor
When will the AVAIL switchlight illuminate?
99% RPM plus 2 seconds
What is the CRJ-900 Powerplant Model Number?
General Electric CF34-8C5
What is the CRJ 700 Powerplant Model Number?
Either General Electric CF34-8C1 or General Electric CF34-8C5B1
What is the thrust rating without APR/with APR?
13,560 lbs without
14,750 lbs with
What is the Max ambient air temperature for takeoff and landing?
ISA + 35°C
What is the Min ambient air temperature for takeoff and landing?
-40°C
What is the Max Altitude for a windmill start?
21,000 ft MSL
Max engine to engine N2 split at ground idle power?
2%
How much of the thrust is produced by core air?
Approximately 20%.
How much thrust is produced by by-pass air?
Approximately 80%.
How many stages of compression do we have?
The engine is equipped with a 10 stage axial flow compressor
What accessories are driven off the N2 accessory gear box? (fish oil plus)
- Engine driven fuel pump
- IDG
- air turbine starter
- engine driven hydraulic pump
- oil pump
- FADEC alternator
What is the engine bleed air used for?
- Engine start
- air conditioning
- pressurization
- wing and cowl anti-ice
What stages of bleed air are used?
Normally 6th stage, 10th stage used when demand exceeds capability of 6th stage
What allows 10th stage bleed air availability?
Air Conditioning System Controller (ACSC) automatically opens the High Pressure Valve (HPV).
How many igniters are installed on each engine?
Two
IGN-A and IGN- B.
What are the required parameters before fuel is introduced during a ground engine start?
20% or greater N2
ITT <120°C
What is the air pressure requirement provided by the operating engine to initiate a cross-bleed start?
42 PSI to a maximum of 80% N2
When will APR arm on takeoff?
Engine speed within 8% of scheduled takeoff power, normal or flex
When will the APR system activate?
Thrust levers in TOGA
Normal or flex thrust scheduled and N1s differ by 15% or greater or when thrust levers set in the MAX POWER detent.
What occurs when the APR system activates?
FADEC commands an N1 speed increase dependent on thrust lever position.
What indication will we have of APR activation?
Green APR icon on operable engine N1 gauge.
If an engine fails during a go-around, will the APR system activate?
Yes.
What is used to deploy and stow the thrust reversers?
Hydraulics L reverser uses hydraulic system #1
R reverser uses hydraulic system #2
How are the thrust reversers deployed?
Thrust levers must be at idle.
The reverse thrust levers are raised by engaging the thrust reverse release triggers. A solenoid lock stops reverse thrust lever movement while the reversers deploy.
Once deployed, the lock releases and N1 may be increased by raising the reverse thrust levers.
What is occurring during thrust reverser deployment?
The translating cowls move aft.
The bypass air is redirected through cascade vanes which redirect the air forward.
What indications will be seen with normal thrust reverser deployment?
Green REV icon on N1 gauges.
When do the thrust reversers need to be either stowed or at idle?
CRJ900: 60 kts
CRJ700: 75 kts
What happens when a thrust reverser inadvertently deploys?
FADEC commands reverser to close and
thrust set to idle on affected engine.
What are the indications of an inadvertent thrust reverser deployment?
Amber REV icon on N1 gauge REV UNLOCKED caution message
What is the normal air source for engine starts?
APU or cross-bleed if doing a single engine taxi.
What source is used if the APU is INOP?
Ground air cart or bottle attached to the high pressure air ground connection to start one engine.
A cross bleed start is then used to start the other engine after clearing it with ground control.
Where is the high pressure air ground connection located?
Under left engine nacelle
When will the starter cut-out during an engine start?
50% N2
