Engines And APU

Question 1

Q.5.1. On initially receiving power, what format are the engine instruments displayed?

Answer 1

NG
A Compact Engine Display

MAX
Secondary Engine Indications

Reference: FRM B737NG 7.3.2.4.1, FRM B737MAX 7.2.2.2

Question 2

Q.5.2. On the NG, what format is required for the engine instruments before the engine is started?

Answer 2

Set the engine displays to the compact format.

Reference: AOM 7.2

Question 3

Q.5.3. On the MAX, which DU is required to display the engine instruments?

Answer 3

Set the engine displays to the Captain’s inboard DU.

Reference: AOM 7.2

Question 4

Q.5.4. When is the engine failure alert, ENG FAIL, displayed in amber on the EGT indicator?

Answer 4

An engine failure alert indication (ENG FAIL) is displayed in amber on the EGT indicator when the respective engine is operating at a condition below sustainable idle [NG (50 percent N2)] and the engine start lever is in the IDLE position.

Reference: FRM B737NG 7.3.2.3, FRM B737MAX 7.2.2.3

Question 5

Q.5.5. What would remove the amber ENG FAIL alert displayed on an EGT indicator?

Answer 5

The alert remains until the engine recovers, the engine start lever is moved to CUTOFF, or the engine fire warning switch is pulled.

Reference: FRM B737NG 7.3.2.3, FRM B737MAX 7.2.2.3

Question 6

Q.5.6. How does the EEC control thrust in the normal mode?

Answer 6

The EEC uses sensed flight conditions and bleed air demand based on autothrottle and/or Flight Deck Crew inputs to automatically set engine thrust.

Reference: FRM B737NG 7.3, FRM B737MAX 7.2

Question 7

Q.5.7. When does the EEC automatically switch to soft alternate mode?

Answer 7

If required signals are not available to operate in the normal mode, the EEC automatically changes to the soft alternate mode.

Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.1

Question 8

Q.5.8. What indication on the Engine Panel would alert the Crew that automatic switching into the soft alternate mode has occurred?

Answer 8

When this occurs, the ALTN switch illuminates and the ON indication remains visible.

                                                                              Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.2

Question 9

Q.5.9. How does an EEC in soft alternate control the engine?

Answer 9

The EEC uses the last valid flight conditions to define engine parameters which allows the mode change to occur with no immediate change in engine thrust.

(opens in a new tab)Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.2

Question 10

Q.5.10. What is the indication on the EEC switch on the Engine Panel if hard alternate mode is manually selected?

Answer 10

When ALTN is selected manually, the ON indication is blanked.

(opens in a new tab)Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.2

Question 11

Q.5.11. What is the effect on the EECs with a loss of either DEU (NG) or either DPC (MAX)?

Answer 11

Loss of either DEU (NG), DPC (MAX) results in a loss of signal to both EECs. The EEC ALTN lights illuminate and each EEC reverts to the [soft] alternate mode to prevent the engines from operating on a single source of data.

(opens in a new tab)Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.2

Question 12

Q.5.12. The hard alternate mode has what affect on thrust?

Answer 12

Hard alternate mode thrust is always equal to or greater than normal mode thrust for the same lever position. Thrust protection is not provided in the hard alternate mode and maximum rated thrust is reached at a thrust lever position less than full forward.

(opens in a new tab)Reference: FRM B737NG 7.3.3.2, FRM B737MAX 7.2.3.2

Question 13

Q.5.13. How long must the APU run before being used as a bleed air source?

Answer 13

Two minutes.

Reference: FRM B737NG 7.4.2.4, FRM B737MAX 7.3.3, AOM 3.8.6

Question 14

Q.5.14. When accomplishing the TERMINATING CHECKLIST, how long must you wait to turn the battery off after the APU GEN OFF BUS light extinguishes?

Answer 14

NG
Two minutes.

MAX
Five minutes.

Reference: AOM 14.2

Question 15

Q.5.15. What is a consideration for APU use during a deicing/anti-icing event?

Answer 15

If not required, the APU should be shut down to eliminate the possibility of deicing/anti-icing fluid entering the APU inlet, which may cause erratic operation or damage to the APU.

Reference: AOM 15.1.9

Question 16

Q.5.16. Which side of the fuel manifold does the APU draw fuel from?

Answer 16

Fuel to start and operate the APU comes from the left side of the fuel manifold when the AC fuel pumps are operating. If the AC fuel pumps are not operating, fuel is suction fed from the No. 1 tank.

Reference: FRM B737NG 7.4.2.1, FRM B737NG 7.4.2.1.1, FRM B737MAX 7.3.2.2

Question 17

Q.5.17. When the APU is the only source of electrical power, what is the difference between load shedding on the ground and in flight?

Answer 17

On the ground, the APU attempts to carry a full electrical load. If an overload condition is sensed, the APU sheds galley busses and main busses until the load is within limits. In flight, all galley busses and main busses are automatically shed.

Reference: FRM B737NG 7.4.2.7, FRM B737MAX 7.3.3.3

Question 18

Q.5.18. Is engine shutdown required for flap area contamination removal?

Answer 18

Yes.

Reference: AOM 15.1.10.1

Question 19

Q.5.19. The MAX has two additional Alerts compared to the NG on the Engine Display per engine, what are the Alerts?

Answer 19

THRUST and FUEL FLOW.

Reference: FRM B737MAX 7.1.1.7

Question 20

Q.5.20. In the MAX, what does the FUEL FLOW Alert indicate?

Answer 20

Illuminated (amber)

Steady - Engine fuel flow is abnormally high when compared to the FMC expected fuel flow.

Blinking - With fuel flow abnormally high, the alert and entire block will blink for 10 seconds and then the alert only will remain steady until the condition no longer exists.

Reference: FRM B737MAX 7.1.1.7, QRH 12.4

Question 21

Q.5.21. In the MAX, what does the THRUST Alert indicate?

Answer 21

Illuminated (amber)

Steady - The thrust is more than commanded thrust; or
- The thrust is less than the commanded thrust.
- Displayed in conjunction with amber N1 command sector for affected engine.

Blinking - With a condition of more than or less than commanded thrust. The alert and entire block will blink for 10 seconds and then the alert will remain steady until the condition no longer exists.

Reference: FRM B737MAX 7.1.1.7, QRH 7.27

Question 22

Q.5.22. In the MAX, what safety feature of the EEC protects against exceedance of engine design limits?

Answer 22

Electronic Overspeed System (EOS).

Reference: FRM B737MAX 7.2.3.5

Question 23

Q.5.23. In the MAX, what indication would you expect to see if the Electronic Overspeed System (EOS) activated?

Answer 23

The amber ENG FAIL alert illuminates. THRUST alert may or may not appear.

Reference: FRM B737MAX 7.2.3.5

Question 24

Q.5.24. How does the EEC provide flameout protection?

Answer 24

An auto-relight capability is provided for flameout protection. Whenever the EEC detects an engine flameout, both igniters are activated. A flameout is detected when an uncommanded rapid decrease in N2 occurs, or N2 is below idle RPM.

Reference: FRM B737MAX 7.2.7.2.1, FRM B737NG 7.3.6.2.1

Question 25

Q.5.25. In the NG, what does the REVERSER light indicate?

Answer 25

• Isolation valve or thrust reverser control valve is not in commanded position.
• One or more thrust reverser sleeves are not in commanded state.
• Auto-restow circuit has been activated.
• A failure has been detected in synchronization shaft lock circuitry.

Reference: FRM B737NG 7.2.3

Question 26

Q.5.26. The MAX has 3 different reverser amber lights on the Engine Panel. What does the REVERSER COMMAND light indicate?

Answer 26

Illuminated (amber) - The reverse thrust lever is not in the down position in flight.

Reference: FRM B737MAX 7.1.5

Question 27

Q.5.27. What does illumination of the REVERSER AIR/GRD amber light indicate?

Answer 27

Illuminated (amber) - The air/ground thrust reverser logic has failed.

Reference: FRM B737MAX 7.1.5

Question 28

Q.5.28. What does illumination of the REVERSER LIMITED amber light indicate?

Answer 28

Illuminated (amber) -

• On the ground - A fault has occurred in the thrust reverser system
• In flight - A fault in the thrust reverser system limits reverse thrust. Thrust reverser will not deploy or reverse thrust will be limited to idle.

Reference: FRM B737MAX 7.1.5

Question 29

Q.5.29. In the NG, what does an illuminated MAINT light on the APU Control Panel indicate?

Answer 29

Illuminated (blue) - APU maintenance problem exists:
- APU may be operated.
- Light is disarmed when APU switch is OFF.

Reference: FRM B737NG 7.2.5

Question 30

Q.5.30. In the MAX, what does the DOOR light on the APU panel indicate when illuminated?

Answer 30

Illuminated (amber) - APU door is not in the commanded position:
- APU door is open when APU is shut down (in air or on ground).
- In flight - door is not in flight position.
- On ground - door is not in ground position.

Reference: FRM B737MAX 7.1.8

Question 31

Scenario

You are on taxi out and you power up to start taxi and go back to idle, the number 2 engine does not decelerate back to idle.

Q.5.31. What could you expect to happen in a MAX?

Answer 31

The EEC commands an engine shut down through the TCMA function due to indicated thrust above the selected idle position.

(opens in a new tab)Reference: FRM B737MAX 7.2.3.4