APU Flashcards
What does the gas turbine auxiliary power unit (APU) provide?
A. AC and DC electrical power
B. AC electrical power and bleed air
C. DC electrical power and bleed air
D. AC electrical power and failure detection
B
How is the oil quantity in the APU oil sump maintained at optimal level?
A. The crew can service APU oil through the oil replenishment system or manually through the gravity oil fill port.
B. The oil replenishment system functions automatically without any crew involvement .
C. The oil sump can be only refilled by maintenance personnel using a pressure oil fill port.
D. The APU oil does not deplete.
A
What fuel tank normally supplies the APU?
A. Aft fuel tank
B. APU fuel tank
C. Left wing collector tank
D. Right wing collector tank
D
What system does NOT use APU bleed air?
A. Wing anti-ice system(WAI)
B. Main engine starting(MES)
C. Environmental control system (ECS)
D. Fuel tank inerting system (FTIS)
A
If a high oil temperature condition occurs while the airplane is in flight:
A. the APU shuts down automatically.
B. the APU remains in operation.
C. the APU shuts down after 60 seconds.
D. an APU FAULT message is shown on the EICAS.
B
What happens first in the normal shutdown sequence initiated by selecting the APU rotary switch to the OFF position?
A. The APU shutdown occurs immediately.
B. The APU door opens fully.
C. There is a 90-second cool down period before the actual shutdown occurs.
D. There is a 1-minute cool down period before the actual shutdown occurs.
D
APU name
SPU300
APU provides :
1 Bleed Air cooling & heating up to
2 Bleed Air for Engine Start up to
3 Bleed Air for fuel tank inserting up to
4 Electric Power
25 000 ft
23 000 ft
25 000 ft
60 KVA - 45 000 ft and 40 KVA till 51 000 ft
Where is located and how is operated the APU door
Located on the upper right side of the fuselage
Electrically actuated , controlled by FADEC
What is the maximum RPM for starting the APU or for windmilling
7% RPM
When can the APU door angle be seen
If a door fault is sensed by the FADEC the APU door angle is displayed in Amber on EICAS page and on Service synoptic and the APU DOOR FAIL CAS message comes on
When does an automatic APU shutdown occurs due to door position?
On GROUND if the the door is NOT fully opened
IN FLIGHT if the door is NOT in the position commanded by the FADEC and if the door is opened less the 45 degrees
How many speed sensors are in the APU
2
When is the FADEC commanding an automated shutdown due to Speed sensors?
1 When an overspeed is sensed by the FADEC
2 With the Failure of both sensors on ground and inflight
How many Temp sensors are?
2
What are the temp sensors used for?
1 Provides Temp info to FADEC for turbine monitor
2 Fuel schedule trim
3 Bleed Control Valve - BCL, modulation
Failure of the Temp sensors
1 On Ground - automatic shutdown
2 In FLIGHT - message APU EGT SENSORS amber CAS comes on
Primary components of the APU
1 Wet Oil Sump
2 Gear driven pressure / Scavenge Pump
3 Oil pressure, Temperature & Quantity Sensors
4 Fuel / Oils / Air Heat Exchanger
What happens If Oil pressure drops bellow a certain value ON GROUND
1 APU shutdown occurs and
2 APU OIL LO PRESS amber message CAS. Then
3 APU SHUTDOWN blue message CAS
What happens If Oil pressure drops bellow a certain value IN FLIGHT
1 APU OIL LO PRESS amber CAS on
2 Protective shutdown is NOT initiated
What happens If Oil Temp rises above a certain value ON GROUND
1 APU OIL HI TEMP amber CAS replaced by
2 APU SHUTDOWN blue message CAS
What happens If Oil Temp rises above a certain value IN FLIGHT
1 APU OIL HI TEMP amber CAS comes on
2 Protective shutdown is NOT initiated
What is the total capacity of the APU OIL SUMP
3.7 quarts (3.6L)
At what value the APU LOW OIL QTY come on
3.4 Qaurts (3.3L)
Even if the real quantity is bellow 3.4 Q the lowest value transmitted by FADEC is 3.4
When APU is replenished the value remain at 3.4 Q until the entire gear box is filled up then rises to the 3.7 Q indication
