Powerplant Flashcards
What section of the engine provides air for the aircraft Environmental Control System (ECS), wing anti-icing, nose cowl anti-icing and engine internal cooling / sealing?
HP compressor
The parameter used to measure forward thrust in the primary control mode is Engine Pressure Ratio (EPR). How is it derived?
By forming a ratio of outlet pressure to inlet pressure
What happens to the engine during water ingestion?
Bleed handling valves are commanded OPEN, continuous ignition is selected ON automatically, and the engine idle speed is increased to ensure engine stability and allow water to pass into the bypass flow.
The FADEC is normally powered by its Permanent Magnetic Alternator (PMA). What happens during engine start or failure of the PMA?
An alternate source of power is provided by aircraft 28V DC essential power
The primary function of the Engine Vibration Monitoring System (EVMS) is to monitor the balance of the rotating assemblies in the engine in order to detect possible mechanical failure. How many sets of probes are used?
Two (2) sets of probes (one primary and one secondary) to measure the amount of rotation on both the LP and HP rotating components
When should an engine be shut down for abnormal EVM indications?
If vibration is accompanied by other failure indications
When might vibrations exceed alert levels and be considered normal?
In icing conditions
At what altitude must the boost pumps be operating to sustain engine operation?
Above 20,000 feet
What’s the primary purpose of the Fuel Cooled Oil Cooler (FCOC)?
It enables engine oil to heat fuel and prevent formation of ice crystals in LP filter and FMU. It also cools the oil.
Name four conditions required for the heated fuel return system to operate?
Not at high power setting, system is armed by selection of FUEL RETURN switch to AUTO, fuel tank temperature drops to approximately 0°C, and crossflow closed
At what fuel tank temperature does the heated fuel return system cease to operate?
Approximately +10°C
What happens during engine shutdown if capacity of drains tank (environmental container) is exceeded?
Fuel is dumped overboard
What three ways can be used to fill the oil tank?
By conventional gravity filling, pressure filling or through the remote replenishing system
When does the Fluid Quantity Indicator (FQI) take a snap shot of the oil quantity and store it as a historical reading?
Five (5) minutes after engine shutdown
How does the FADEC alternate channels for consecutive ground starts?
It changes channels every time you cycle the FUEL CONTROL switch and changes exciters/igniters every other time unless there’s a start anomaly.
True/False: When a normal ground start attempt has been aborted due to anomalies, the FADEC automatically selects the other igniter on the following normal ground start attempt.
True
True/False: The ignition systems are capable of being continuously energized by pilot selection of continuous ignition.
True. There’s no time limitation; however, continued or very frequent use will shorten igniter life.
Which type of engine start uses just one igniter?
Normal ground start including crossbleed start and engine start – battery power only. Both igniters are used for alternate engine ground start and all air starts as well as inclement weather mode, auto-relight, and quick relight.
What happens when you select MASTER START switch to ON?
It signals FADEC to arm the automatic start sequence for start valve and ignition, opens isolation valve and shuts off the right pack.
During an engine start, when would you expect the starter air valve (SVO) and IGN icons to extinguish?
Approximately 44% HP
What’s the only time you’re fully FADEC protected during an engine start?
During a normal start on the ground using the MASTER START switch
What’s the caution associated with opening the starter air valve manually?
Wear high temperature protective gloves and exercise caution
What is rotor bow?
It’s a phenomenon where LP and HP shafts warp or bow due to uneven temperatures after shutdown.
When would you expect the FADEC to perform an automatic rotor bow avoidance procedure during engine start?
If the engine has been shut down for more than twenty (20) minutes, but less than five (5) hours
What would be the corrective action for an Autostart Abort?
Select the associated FUEL CONTROL switch to OFF and select ENGINE START MASTER switch to OFF
Alternate start mode is selected when MASTER CRANK switch is placed to ON. In this mode, what can the FADEC not command?
Ignition: the crew must manually select continuous ignition to ON
What are the two sources of air for rotating the engine during airborne engine start?
Air from inside (i.e. from other engine or APU) or air from outside (i.e.windmilling).
Name the three (3) airstart procedures.
Normal Airstart – Automatic, Manual
Airstart – Starter-Assist, and Manual
Airstart – Windmilling
Which airstart method is preferred?
Normal Airstart – Automatic
When using the Normal Airstart – Automatic checklist, what does the FADEC use to determine whether to assist with bleed air or windmill?
Airspeed (i.e. less than 250 KCAS, the FADEC opens the starter air valve and greater than 250 KCAS, the starter air valve remains closed)
Under what conditions would you use the Manual Airstart – Windmilling procedure?
If the starter was inoperative or in icing conditions
What’s the auto-relight mode?
It’s automatically initiated by the FADEC for engine flameout and rundown. In this mode, the FADEC energizes both igniters continuously and schedules fuel flow until rpm stabilizes.
What’s the quick relight mode?
Provides a means of automatically relighting the engine if the FUEL CONTROL switch has been selected to the OFF position and then reselected to the RUN position within 30 seconds. When activated, fuel is commanded on and both ignition systems are switched ON.
How are the engines controlled and what are the benefits?
Engine control is achieved by dual channel Full Authority Digital Engine Control (FADEC) system for improved handling, fuel efficiency and longer engine life.
Name the three (3) major components of the FADEC?
Electronic engine controller (EEC), data entry plug (DEP), and permanent magnetic alternator (PMA).
What are the requirements for engaging the autothrottles on takeoff?
Valid EPR rating selected, valid speed target selected, and > 1.05 EPR
Why do autothrottles go into hold mode at 60 kts during takeoff?
Autothrottle servos are deenergized to prevent unwanted thrust reductions during critical takeoff between 60 kts airspeed, rotation and climbout to 400’ AGL.
When does the autothrottle system come out of hold?
400’ AGL
What affect does the hold mode have on a rejected takeoff?
It allows you to abort with no friction on the throttles
What happens if you push TO/GA during a fully coupled two engine ILS approach?
Go-around is commanded (initial 9° pitch up and wings level), both autopilot and autothrottles remain engaged, power levers advance to go-around power, and the FMS sequences to the missed approach procedure.
How can the autothrottles be disconnected?
Push either quick disconnect switch, toggle either engage/disengage button, or manually adjust the throttles.
How is the engine controlled in the Alternate mode?
With LP
Name the three idle settings.
Flight, approach (i.e. high idle), and low or ground idle
What’s the requirement for approach idle?
Flaps > 20°, aircraft in flight and no wheel spin-up
The FADEC normally governs the engine power using EPR as the primary control parameter; however, as an alternative, the FADEC can also use LP fan speed as the engine control parameter. What’s the changeover between these two modes of operation called?
A reversion
What’s the difference between a soft and hard reversion?
A change to alternate control mode, which is initiated by the FADEC, is known as a soft reversion. A change initiated by the pilot, through selections made on the cockpit SMC (Sensor page), is known as a hard reversion.
What’s the downside to the alternate control mode?
You lose FADEC protection, you lose autothrottles, and you can’t dispatch in alternate control.
At a given throttle position (other than idle), which engine would provide higher thrust: a hard reverted engine in alternate LP control mode or an engine in the normal EPR control mode?
The hard reverted engine in alternate LP control mode would provide higher thrust
True/False: To prevent sudden changes in thrust from occurring when hard reverting the engine control mode, the throttle lever should always be placed in the mid position before selecting or de-selecting alternate control on the SMC.
True
How would you describe thrust reverser operation?
Electrically controlled and hydraulically operated
When would thrust reversers be available after landing?
With wheel spin-up or weight-on-wheels
Were the thrust reversers considered for landing distance certification?
Not on dry runways; they were considered for wet
How is the engine controlled in the reverse thrust region?
With LP
Describe thrust reverser indications.
White REV – unlocked
Green REV – fully deployed (maximum reverse thrust available)
Amber REV – uncommanded deployment on the ground: engine limited to idle
Flashing red REV – deployment in flight: engine limited to idle
Can an inoperative reverser be locked out?
Yes
