HYDRAULIC SYSTEM
PRESSURIZATION LIMITS:
Max differential 9.1psid Max differential for T/O or Landing 0.11psid
ENGINES
*Describe the Engines and their Gauges:
GE90-90B engines, rated at 94,000# thrust (as of 8/99). (increased in 1999 from 92.5k for longer TBO’s).
Notes: Originally rated at 84,900# & expected to "grow" to over 115,000# (same engine), with later models. Blades are a wide-chord design to improve efficiency.
10 stage dual dome compressor.
Composite fan blades with titanium leading edges for impact strength. Aluminum spacers at blade root.
Utilizes Mobile 254 oil.
3" thick Kevlar containment band High by-pass ratio (8.4:1).
ELEC controlled, HYD actuated fan-air reversers. (Does NOT reverse the turbine section). Controlled by the dual channel EEC Mode:
NORM:
receives input from the crew through thrust levers. (previously called throttles). AIMS calculates ref thrust (max limit).
EEC meters fuel to allow N1 to match commanded N1 thrust lever position. max RATED thrust available in any phase (max throttle).
provides N1 & N2 RPM overspeed protection.
controls Min-Idle & Approach-Idle as needed (flaps in LND range or EAI ON). ALTN:
manually - "hard", or automatically - "soft" selected. (ATS remains engaged). N1 & N2 overspeed protection remains in effect.
thrust reference remains in effect.
there is NO thrust limit protection. (retard the thrust levers before selecting “hard”). SOFT - N1 goes blank. Set both engines to HARD (manual) ALTN.
START:
initiates engine start cycle.
returns to NORM at starter valve CUTOFF. 2 Igniters per engine. (Controlled by EEC).
auto-start selects & alternates igniters (uses both for Abnormals). NORM:
auto ignition for both igniters as needed. (Fuel Control must be in RUN). CON:
both igniters operate continuously (if Fuel Control is in RUN). AUTOSTART: ON:
controls Fuel & Ignition, & monitors start/restart. shuts OFF Ignition after successful start.
monitors N1, EGT, N2, FF, & duct pressure (NOT oil TEMP/PRESS). arms auto relight system
Airborne Vibration Monitors
monitors both N1 & N2, displays the higher of these two vibration levels. or, if it can't tell if it's N1 or N2; BB (broad band) is displayed.
Bleed Air used for: (see list under pressurization). ASCPC (Air Supply & Cabin Pressure Controller):
modulates PRSOV's (bleed valves) to control PNEU duct temp. (ENG) ON/Blank: bleed valve OPEN (automatic function). (ENG) ON/OFF: auto closed due to:
protective bleed shutdown or duct leak. valve failed CLOSED.
engine is not running. Eng Fire switch PULLED.
(ENG) Blank/OFF: bleed valve selected CLOSED manually. (APU) AUTO/Blank: controlled automatically.
(APU) AUTO/OFF: auto closed due to: duct leak.
valve failed CLOSED. APU fire switch PULLED.
(APU) Blank/OFF: manually selected CLOSED. (ISLN) AUTO/Blank: controlled automatically. (ISLN) AUTO/OFF: auto closed due to:
duct leak or bleed loss. valve fails CLOSED.
(ISLN) Blank/OFF: manually selected closed.
1. *What are the primary engine instruments?
• N1 & EGT.
2. *What is the minimum oil quantity before and after start?
• min 23 before start (max reading is 24 quarts).
• min 18 after start (defined as before brake release). (may see less than 15-17 after start on a cold day). Note: This is an ETOPS requirement.
3. *What happens to Pack & Start valves during an engine start?
• engine start valve OPENs when the switch is positioned to START. • both pack valves automatically CLOSE to maximize air to starter.
Note: If the second engine is not started within a short time, the pack valves OPEN again. Note: Once the engine supplies bleed air to the manifold, the associated ISOL valve CLOSES. 4. When should you take action for NO Oil Pressure during start?
• cutoff fuel control if NO oil pressure after initial EGT rise (light-off).
Note: During extreme cold wx ops: cutoff fuel if NO oil pressure when eng stabilizes at idle thrust.
5. *What does cutting off the Fuel Control do?
• closes both the spar fuel valve & the eng fuel control valve, deactivates the ignition, closes the eng bleed valve, & releases the fire switch lockout.
6. *Can the EEC initiate a second or third start?
• yes: if a hot-start, hung start, compressor stall, or no-start occurred the EEC will motor the engine for 6-30 seconds and try again using both ignitors.
• a third attempt will also be tried then, if failed, the EEC aborts the start, motors for 30 seconds & shuts OFF the starter. Note: No restart attempt for: LO air pressure to starter, starter shaft failure, or starter duty time exceeded.
7. *When would you move the Fuel Control to RUN during a manual start?
• at max motoring (min 22% N2).
8. *What is the purpose of "motoring " the eng after an Aborted Start?
• clear the fuel out of the combustion chamber (otherwise you get a BIG boom!). • cool the engine evenly after a hot start (fuel was all burned up).
Note: EEC automatically motors 6-30 seconds if aborted during Auto-Start. Note: If manual start: motor for 30 seconds.
9. Why are the spirals painted on some large high bypass engines? • to frighten birds away from the engine inlet.
10. *What is the indication of an engine failure on T/O? (IAS < V1).
• aural ENGINE FAIL, PFD "Eng Fail" annunciated, & M-Warning lights. (either engine not producing commanded thrust).
11. What is the indication of low Oil Quantity? • white background & "Lo" beside gauge. • measures quantity of the reservoir. 12. Where is the Oil Temp & Pressure measured?
• downstream of the fuel/oil heat exchanger & prior to the engine fuel controller. 13. How & where is the Fuel Flow measured?
• by the fuel flow transmitter downstream of the engine fuel valve. 14. What is the max Reduced Thrust allowed?
• never less than associated climb power (don't need to push power up to achieve climb thrust). • max 25% from a certified rating (FAR).
15. When would you use derated T-O1 or T-O2?
• never at CAL. This requires Vmcg calcs which limit you to that specific derated thrust in case of an engine failure or windshear or anything else while on the runway.
Note: Assumed temp/reduced thrust always allows use of full thrust to recover from a failed engine if desired.
16. *When does the Ignition come ON automatically? (selector in NORM).
• during manual start when fuel control raised to RUN. • during in-flight auto-start attempts (both ignitors). • with all flap settings. (IE. out of UP).
• with EAI. • during an RTO.
17. What is the power source for the Igniters? • main AC, backed up by Stby AC.
18. Why is it important on the Engine Auto-Start OFF checklist, to return the Auto-Start switch to AUTO after starting both engines?
• arms the quick inflight relight features of the ignition system.
19. *What is the Auto-Relight function?
• flameout protection: activates both ign when the EEC senses a rapid decrease in N2 or less than idle N2 RPM.
20. *When should CON-Ignition be selected?
• heavy rain, severe turbulence, and volcanic ash encounters. 21. What is the indication of MCT being exceeded by the engine?
• digital readout, box, & dial turns AMBER.
Note: On T/O or G/A, the amber warning is inhibited for 5 minutes.
22. *What is the indication if the EGT, N1, or N2 red line is exceeded?
• digital readout, box, & dial turns RED. (if N2 exceeded: brings up secondary engine indications to EICAS). Note: Remains RED until the CANC/RCL button pushed (even then, it is retained in memory).
23. If the EICAS lower display is blank, what will occur if a secondary engine indication is exceeded? • the secondary indications will appear automatically on the lower unit.
• if the display has failed or is in use for another display (such as NAV), the secondary will appear in compacted form on the upper EICAS display.
Note: Secondary indications cannot be cleared/replaced until exceedance is reduced. 24. *How many start attempts will the Auto-Start system make in-flight?
25. When are Secondary Engine Indications automatically displayed? • power up.
• fuel control CUTOFF inflight. • fire switch PULLED inflight. • secondary parameter exceeded. • N2 RPM < idle inflight.
26. *What are the immediate action items for Dual Engine Flameout? (Check current flt manual!)
• Fuel Control Switches (Both)...CUTOFF, then RUN. • Ram Air Turbine Switch...PUSH
27. When can full Reverse Thrust be achieved?
• after interlock release (full reverser sleeve deployment) by moving the reverse levers full UP. • EEC will monitor & control max reverse. (as well as reverse sequence).
Note: Thrust reversers are inhibited by the EEC inflight or with that specific engine shut down.
28. *What occurs to the automated flight systems when reverse is selected?
• disengages the ATS.
• deploys the auto speed brakes (even if not armed).
• A/P remains engaged if in Autoland (continuing rudder steering to maintain LOC). 29. If a reverser fails to stow, what should your action be?
• do NOT cycle the reverser.
• do NOT add a little thrust (it's a HYD reverser, not PNEU).
• you may bend (twist) the cowl tracks if any attempt is made to fix it. • shut off the engine & have mx fix. (Consider a tow-in).
30. In AUTO, what is the normal sequence for the ASCPC ISOL valves? • ground air attached all valves OPEN • APU ON & ENGs OFF all valves OPEN
• starting Lt Eng L & C OPEN, R CLOSED • starting Rt Eng R & C OPEN, L CLOSED • crossbleed start all valves OPEN
• one eng out (in-flight) all valves OPEN
• in-flight (normal) L & R OPEN, C CLOSED (powers associated ADPs) 31. What main air systems are run off the left body duct?
• L WAI, L Pack, L Trim Air, C1 Air HYD Demand Pump, Aft & Bulk Cargo Heat. • (Rt body duct = R WAI, R Pack, R Trim Air, C2 ADP).
32. *What bleed leak protection is provided?
• both struts, both wings (from strut, inboard), body duct (aft to APU & X-body with isol valves) have bleed leak overtemp/overpressure detectors.
- operates automatically: detects & isolates sections of ducts using the supply bleed valves and the bleed air isolation valves.
- may take up to 3 minutes per attempt to isolate the system (logic system waiting to see cooling take place). 33. Why not use the ATS (both ARMED) after loss/shutdown of an engine?
• good idea Bill – it will keep the throttles together & minimize the chance of grabbing the wrong thrust lever.
• since the fuel control lever is CUTOFF, moving the thrust lever does nothing to the system. Having the ATS move it for you will prevent many accidental ATS “HOLD” occurrences & possible loss of airspeed.
Note: There is no Boeing prohibition against this. CAL agreed to keep it OFF to train pilots in ATS inop approaches. However, in a real situation, its use could be a big help and a safer condition.
34. What engine instruments are active prior to engine start? • N1, N2, oil quantity, vibration monitors.
• balance of primary or secondary instruments become active with N2 rotation (approx. 5%+).
• fire switch pulled, start lever OFF, duct leak, duct overheat, or duct over pressure. 36. When is Approach Idle automatically selected?
• EAI ON, flaps in landing range (25-30), 1 ADP is inop & flaps are deployed, or if an opposite eng bleed valve is closed (for example, single engine).
37. *When is TAC inhibited?
• while reverse thrust is active or < 70 kts on the ground. 39. What is “Shingling”?
• as large cord fan blades heat up and cool, and are subjected to large centrifugal forces, they “grow” (extend) over time. • shingling is the rubbing of fan blades against the composite cowling ring.
Note: Abnormal wear marks between the fan blades and the cowling ring are caused by shingling and should be checked and reported on preflight walkaround.
Note: On the B777 GE engines, the fan blades are LRUs (individual Line Replacement Units).