777 Engines/APU

Describe the N1 indications on EICAS display

RED - N1 RPM limit

AMBER - Max N1 Rated thrust computed by EEC

Green - ref N1 limit

Magenta - FMC N1 target in VNAV when A/T in THR/THR REF or not engaged.

White - Commanded N1

Describe Soft and Hard EEC alternate modes. What protection and features does EEC alt mode provide?

Both modes provide Overspeed (N1 + N2 red line - EEC reduces fuel flow) protection and Thrust reference targets.

Soft - EEC downgraded itself, no thrust change if thrust lever stationary. Both NORM/ALTN show but EEC is ALTN.

- A/T remains engaged

Hard - Manual switch selection to Alternate mode. NORM disappears and N1 reference/target now computed by FMC. Command + THR Ref lines given.

- Thrust may change to set commanded N1 since FMC schedules equal or greater thrust for same lever pos'n.

- Possible overboost since max thrust is less than firewall and THRUST LIMIT protection NOT provided.

- Firewall only for Emergency use.

Describe the AUTOSTART ground start sequence

Initiate by selecting START on selector and FUEL CONTROL sw to RUN (opens spar valve only)

- START selector opens starter air valve and dry motors engine

- EEC opens Engin fuel valve and energizes ignitor(s) at the appropriate N2

- EEC meters fuel flow rate, monitors EGT and N2 RPM and other parameters until idle.

- Start selector returns to NORM at set N2 RPM

What parameters does autostart NOT monitor in 300 vs 77F? And what items does autostart attempt 3X?

300 - Oil temp and pressure

77F - Oil temp

3 attempts on Group 1 faults:

S. - compresser Stall

H - Hot start

H - Hung start

E. - no EGT rise

Group 2 faults: no additional attempts

- Start shaft fail / No N1 / Insufficient air pressure for starter / Starter Duty cycle exceeded.

Note:

- when N2 RPM < Cutout speed, EEC cuts Fuel and Ignition and motors 4s before 2nd and 3rd attempt.

- 2nd attempt BOTH Ignitors used and

- 3rd attempt adjusts Starting Fuel flow

When is time critical warning available for ENG FAIL on T/O

- starts @ 65kts - Red ENG FAIL on PFD (w/Master Warning + Voice) if actual THRUST < Commanded or insufficient THR increase rate

(New msg inhibits @ V1 - 6kts -- No new red ENG FAIL on PFD until landing)

- Becomes Caution msg ENG THRUST L or R after 6kts

-Fire warning available until V1/r - inhibits until 400'/ 25s

- Caution msg ENG FAIL L or R remains until recovered or shutdown.

When will the APU start automatically?

In Flight - L+R AC transfer busses lose power. APU selector position doesn't matter

The pneumatic starter operates when pressurized air is available. If not, the electric starter starts the APU.

At what maximum altitude can the APU provide electrical power and bleed air?

Electrical (and start up) throughout A/C envelope, BLEED up to 22000'.

- Electrical has priority

Describe the thrust limit and Overspeed protections of EEC

Normal:

- EEC sets thrust N1 based on Thrust lever position, whether A/T or Manually. Continuous computation of max N1 sets firewall as physical limit = Max rated thrust

- N1 and N2 overspeed protection (red line) by limiting fuel as red line is approached

When will the EEC select APP IDLE?

- EAI operating

- F25 or greater

- 1 Hydraulic air driven pump inop and flaps out of up.

- Opposite ENG BLEED valve closed

What is the meaning of ENG AUTOSTART msg during ENG Manual start?

Autostart did not start the engine or

AUTOSTART sw off w/ FUEL CONTROL sw in RUN and RPM is low

When will the EEC select both Igniters?

ISAFE

- In flight start

- SHHE detected (Auto #2 - Stall Hung Hot EGT)

- Auto relight,

- Flaps out of Up - flameouts

- EAI On - flameouts