Powerplant Flashcards
Powerplant
What the primary engine parameters displayed on EICAS?
• EPR (Engine Pressure Ratio). • N1. • EGT (Exhaust Gas Temperature).
What are the secondary engine parameters?
• N2. (2nd stage intermediate compressor). • N3 (3rd stage HP compressor). • FF (Fuel Flow). • Oil temperatures & pressures. • Engine vibration.
What pilot actions would cause automatic display of the secondary engine parameters?
• Fuel control switch moved to cutoff in FLT. • Engine fire switch pulled.
How is the EGT maximum continuous limit indicated?
Indicated by an amber band.
When are EGT indications inhibited from changing to amber?
During T/O & GA, 5 minutes (10 minutes W/ engine failure).
What does the EGT redline represent?
Max. T/O limit.
After an exceedance, how can the red box be removed from EICAS?
By pushing the cancel/recall switch on the DSP.
Which two parameters reverse their colours when abnormal?
• (Low) oil quantity. • (High) engine vibration. Both change to black text on white background.
How is maximum EPR indicated?
Amber line at the top of the EPR dial.
What are the parameters for setting thrust in the normal and alternate modes?
• Normal: EEC uses EPR (N1 for 773ER). • ALTN mode: EEC uses N1.
How can maximum rated thrust be obtained?
By moving thrust levers to full FWD position (AVBL any phase of FLT).
What the two types of alternate mode?
- Soft (when EEC automatically switches an engine to ALTN mode and the EEC mode switch remains in NORM)
- Hard (when ALTN is manually selected on an EEC mode switch).
Which type of alternate mode is manually selected?
Hard ALTN mode.
How is the autothrottle affected by alternate mode?
Autothrottle remain engaged in hard & soft ALTN mode.
When is maximum rated thrust achieved in alternate mode?
Max rated thrust reached at a thrust lever position < full FWD (thrust protection not provided).
What protections are available in alternate mode?
N1 & N2 red line (overspeed) protection
How does the EEC protect against rotor overspeed?
EEC commands reduced FF when approaching overspeed.
Why is approach idle selected with FLAPS 25
Approach idle decreases acceleration time for a GA.
During autostart, what do the fuel control switches control?
Moving the fuel control switch to run (during autostart) opens the spar fuel valve.
At what N3 RPM does starter cutout occur?
50%. Start selector releases to NORM position.
When does the EGT maximum start limit red line disappear?
After the engine has stabilised at idle.
Which fuel valve is operated by moving the fuel control switch to RUN?
• During autostart: Spar fuel valve. • Manual start: Spare & engine fuel valve.
What two parameters are not monitored by autostart?
Oil pressure & temperature.
After an aborted ground start, at what EGT will a re-‐attempt be performed?
< 100oC.
How many times will autostart attempt a ground start?
2
For which events will autostart not attempt to re-‐start?
• No N1 rotation. • Low starter air pressure. • Starter shaft failed condition. • Starter duty cycle timer expires. • Start aborted ABV starter cutout speed.
After an aborted flight start, at what EGT will a re-‐attempt be performed?
200oC.
During a manual start, when are fuel and ignition introduced?
As soon as the fuel control switch is positioned to run.
When is a crossbleed start indication displayed next to the N3 indication?
If airspeed < airspeed recommended for windmilling start.
In flight, how many attempts will the autostart perform?
In flight, autostart makes continuous start attempts (until engine either starts or the pilot aborts the start attempt by positioning the fuel control switch to cutoff).
How many ignitors are used for in flight starting?
Both of the 2 ignitors.
When is the auto-‐relight function activated?
When engine is at or BLW idle W/ fuel control switch in run.
What are the limitations for engine oil quantity?
• No maximum quantity limit. • There is a low oil quantity limit (causes automatic display of secondary engine display W/ black numbers on white background).
How are the fan reversers activated?
Hydraulically (L hydraulic system powers L reverser, R hydraulic system power R reverser).
When can maximum reverse thrust be achieved?
Firstly, reverse thrust can only be used on the GND W/ engines running (EEC inhibits reverser isolation valve). Max. reverse thrust can be achieved when reverser fully deployed & interlock releases (allowing reverse thrust levers to be raised to max. reverse thrust position).
What does a BB vibration level indicate?
Indicates that the vibration monitoring system cannot determine the source (N1, N2 or N3). BB (broadband) displayed for affected engine. BB is the average vibration detected.
What is the limitation for engine vibration?
No certified vibration limit (but high vibration levels displayed in secondary engine parameters).
Which rotor viration is most likely to caust tactile vibration ?
N1 (low pressure fan).
When will the ENG FAIL message appear on the PFD?
If actual thrust < commanded thrust during T/O between 65 & 6kts BLW V1.
Which EICAS message indicates that actual thrust is significantly less than the commanded thrust?
ENG THRUST L or ENG THRUST R
