Engines Flashcards
N1 or N2 redline
Operating limit
N1/N2 red display
Operating limit exceeded
EGT amber band
Lower end of band = max continuous limit
EGT amber display
Max continuous limit exceeded
EGT redline
Takeoff limit (additional redline displayed for start limit)
EGT red display
Max takeoff or start limit exceeded
What is indicated by a LOW OIL PRESSURE Alert?
Oil pressure at or below redline
What is minimum oil quantity for dispatch?
12 quarts
What conditions cause the ENG FAIL Alert to display?
Start Lever IDLE and N2
What is indicated by the A/T LIM (Autothrottle Limit) annunciation above the N1 indicators?
FMC not providing valid N1 limit values – when this happens, A/T computer calculates a degraded N1 limit
Each engine has two igniter plugs. Which buses are they powered by?
- Left igniter Associated AC Transfer Bus
* Right igniter AC Standby Bus
With ENGINE START Switch in AUTO, when is ignition provided?
Ignition to selected igniter when engine running and
• Flaps extended below 18,000’, or
• Engine anti-ice on
Ignition to both igniters with Start Lever IDLE and
• Uncommanded rapid decrease in N2, or
• N2 below idle RPM
Which igniters are normally activated with ENGINE START Switch in CONT?
With engine operating and Start Lever in IDLE, the selected igniters are activated
With Start Lever in IDLE and ENGINE START Switch in CONT, when is ignition from both igniters automatically provided, regardless of position of Ignition Select Switch?
When N2 drops below idle
Which igniters are activated with ENGINE START Switch in FLT?
With Start Lever in IDLE, both igniters are activated
When must ENGINE START Switch be selected to CONT?
- Heavy rain
* Emergency descent
When must ENGINE START Switch be selected to FLT?
- Volcanic ash
- Severe turbulence
- High engine vibration
- Loss of thrust on both engines
What normally occurs when thrust reversers are deployed?
- Electro-mechanical lock releases
* Isolation valve opens (if on ground or
When are thrust reversers enabled for deployment?
On the ground or
What normally occurs when thrust reversers are deployed?
- Electro-mechanical lock releases
* Isolation valve opens (if on ground or
What normally occurs when thrust reversers are stowed?
- Idle reverse selected when Reverser Lever lowered to Detent No. 1
- Allow RPM to decelerate to idle reverse, then move Reverser Levers full down (do not pause between Detent No. 1 and stow position)
- Thrust reverser control valve moves to stowed position when Reverser Lever lowered to stow position
- Amber REV displayed above N1 indicators (as hydraulic pressure moves translating sleeves forward)
- Amber REV extinguishes (as isolation valve closes and electro-mechanical lock engages)
When is the auto-restow circuit activated?
When actual reverser sleeve position disagrees with commanded position (incomplete stowage or uncommanded movement toward deployed position)
What happens when the auto-restow circuit is activated?
It opens the isolation valve and holds the thrust reverser control valve in the stowed position until the reverser is commanded to deploy or maintenance action is taken
What is indicated by the REVERSER Light on the aft overhead panel?
- Auto-restow circuit activated
- Thrust reverser control valve not in commanded position
- Isolation valve not in commanded position
- Sleeve(s) not in commanded position
- Synchronization shaft lock circuitry failure
Will the REVERSER Light illuminate during normal operation of the thrust reversers?
Yes, it will normally be on when reverser is commanded to stow. Light should go out within 10 seconds, when isolation valve closes – if on more than 12 seconds, a malfunction has occurred and M/C + ENG Sys Ann Lt will illuminate.
Describe idle modes selected by the EECs:
Ground Idle Used for all ground operations
Flight Idle Used for most flight operations
Approach idle Used in flight if:
• Flaps in landing configuration, or
• Engine anti-ice on
If flap/anti-ice signals unavailable, approach idle automatically selected below 15,000’. Approach idle automatically reverts to ground idle 5 seconds (3LC> 2 seconds) after touchdown.
Each EEC has two independent channels. Can they be manually selected?
No, the EEC automatically alternates between channels with each start attempt or if the operating channel fails
What is indicated by the ENGINE CONTROL Lights?
“No go” fault in engine control system (light operates on ground only – it is inhibited from 80K during takeoff to 30 seconds after touchdown)
Describe idle modes selected by the EECs:
Ground Idle Used for all ground operations
Flight Idle Used for most flight operations
Approach idle Used in flight if:
• Flaps in landing configuration, or
• Engine anti-ice on
If flap/anti-ice signals unavailable, approach idle automatically selected below 15,000’. Approach idle automatically reverts to ground idle 5 seconds (3LC> 2 seconds) after touchdown.
Describe EEC Normal mode of operation:
Indicated by white ON in view on EEC Switch
EEC uses sensed flight conditions and bleed air demand to calculate N1; compares commanded to actual N1 and adjusts fuel flow to achieve commanded N1.
Describe EEC Soft Alternate mode of operation:
Indicated by white ON and amber ALTN on EEC Switch
EEC automatically switches to this mode when required signals unavailable; uses last valid flight conditions to define parameters – no immediate change in thrust occurs, but as conditions change, thrust rating may be too high/low.
Describe EEC Hard Alternate mode of operation:
Indicated by amber ALTN in view on EEC Switch
Automatically reverts from soft alternate to hard alternate if thrust levers retarded to idle (no change in indication when this occurs); or, hard alternate mode can be manually selected by pushing EEC Switch (blanking ON indication). In hard alternate mode, EEC reverts to alternate thrust schedule (≥ normal mode thrust for same thrust lever position).
What limitations apply for takeoff with EECs in Alternate mode?
- Both EECs must be in ALTN
- Use 26K max thrust (27K max, if planned)
- Do not use FMC takeoff N1 or QRH V-Speeds
- Do not use autothrottle for takeoff
What structural protection is provided by the EECs?
N1 and N2 redline overspeed protection – EECs do not provide normal EGT redline exceedance protection
What abnormal start protection is provided by the EECs?
- Impending hot start (rapid EGT rise or EGT approaching start limit; indicated by flashing white box around EGT digital indication; no automatic shutdown)
- EGT start limit exceeded (indicated by red EGT box and dial; EEC shuts off fuel and ignition; display turns white when temp drops below start limit; after both engines shutdown, box again turns red to remind crew of exceedance)
- Wet start (no EGT rise within 15 seconds after Start Lever IDLE; EEC shuts off fuel and ignition)
During a normal engine start, what are the indications that the start valve has closed?
ENGINE START Switch returns to AUTO (at 56% N2) and START VALVE OPEN Alert extinguishes
What are the stabilized idle indications (ISA, @ S.L.)?
N1 20%
EGT 410°C (320–520°C)
N2 59%
FF 600pph
What are the starter duty cycle limits?
Maximum of 2 minutes on per start attempt, with minimum of 10 seconds between attempts
Engine Start Abort conditions:
- No N1 rotation (before start lever raised to idle)
- No EGT rise (within 10 sec ground/30 sec flight, after Start Lever IDLE)
- No, or very slow increase in N1/N2 (after EGT rise)
- EGT rapidly approaching or exceeding start limit
- No oil pressure indication (by stabilized idle)
No N1 rotation (before start lever raised to idle) actions:
ENGINE START Switch……………………………………………………….AUTO
No EGT rise (within 10 sec ground/30 sec flight, after Start Lever IDLE) actions:
Start Lever………………………………………………..CUTOFF
Motor 60 seconds, then ENGINE START Switch……………………………………………………….AUTO
No, or very slow increase in N1/N2 (after EGT rise) actions:
Start Lever………………………………………………..CUTOFF
Motor 60 seconds, then ENGINE START Switch……………………………………………………….AUTO
EGT rapidly approaching or exceeding start limit actions:
Start Lever………………………………………………..CUTOFF
Motor 60 seconds, then ENGINE START Switch……………………………………………………….AUTO
No oil pressure indication (by stabilized idle) actions:
Start Lever………………………………………………..CUTOFF
Motor 60 seconds, then ENGINE START Switch……………………………………………………….AUTO
What actions do you take if any Engine Start Abort conditions occur after starter cutout?
Re-engage starter at 20% N2 by selecting ENGINE START Switch to GRD, then motor 60 seconds
What actions are required if an engine fails to shutdown normally (e.g., EGT and fuel flow do not decrease)?
Pull the Fire Switch to shut off fuel (make AML entry)
