Engines and APU

Question 1

When in ENGINE FAIL light available and when will it come on?

Answer 1

80kts to V1

11% differential in N1

Question 2

What is flight idle? What is approach idle and when does it apply?

Answer 2

Flight idle- when throttles are at idle FADEC will maintain a minimum RPM for engine operation

Approach idle occurs when A/I selected on or flaps or slats extended. Increases N1 12-14%

Question 3

Describe operation of the thrust reversers- GE vs PW.

Answer 3

GE- pneumatically deployed
PW- hydraulically deployed

1 & 3 stuck at idle until reverser fully deploys (interlock)
#2 stays at idle until fully deployed and nose gear on ground (FADEC controlled, no interlock)

Question 4

APU shutdown cycle

Answer 4

Using only APU electrical- 60 second shutdown

Using APU air- additional 90 seconds

Question 5

What is the primary job of FADEC?

Answer 5

N1 over speed protection

Question 6

What inputs does FADEC require to stay in primary mode?

Answer 6

Both CADCs talking to ECU

Question 7

What is FADEC reversionary mode? When will it happen?

Answer 7

SELECT & ALTN lights illuminated
SELECT FADEC ALTN lvl 2
Uses last valid CADC data
No overspend protection

Question 8

What is FADEC alternate mode? How does it happen?

Answer 8

After FADEC button selected to ALTN
Uses charted data
No overspeed protection
Will never result in decrease of thrust
PW- ATS not available

Question 9

What is FADEC special alternate mode?

Answer 9

When throttle is pushed through the FADEC bar
Still get overspeed protection
SELECT and ALTN both illuminate
ATS not available if any throttle pushed bar

Question 10

MSC functions

Answer 10

APU
Pitot, AOA, TAT heat
Eng ign and start sequence
Cargo door test
Emergency lights battery test
Cargo fire detection system test

Question 11

What are EGT limits for start? GE and PW

Answer 11

GE- 750

PW- 535

Question 12

What is the power source for the APU panel?

Answer 12

DC powered

Question 13

At what N1 and N2 does the APU normally run and why?

Answer 13

Always runs at 100% N2 to provide stable electrical current

N1 varies based on bleed demands

Question 14

How is fuel provided to the APU?

Answer 14

No pumps on- uses D.C. Start pump (controlled by MSC). Runs for 90 seconds after APU start
Pumps on- uses AC pump (#2 left aft pump)

Question 15

What does a flashing ON light on the APU start switch mean?

Answer 15

The APU did an auto shutdown due to fire

Question 16

What is the power source of the igniters?

Answer 16

A- LEAC

B- REAC