Power Plant and Ignition Flashcards
How many spools are there and how are they designated?
twin spool (2), LP and HP
N1 N2
What does each spool drive?
LP Spool: singe fan, 3 stage intermediate pressure compressor, 3 stage LP turbine
HP Spool: 12 stage HP compressor, 2 stage HP turbine
What does the starter drive?
HP spool
What does the combustion section consists of?
10 interconnected liners with a fuel spray in each.
2 igniter plugs on 4 and 8 are installed. on each engine.
How is the airflow split up as it passes through the engine?
3 to 1 by pass ratio
What could cause an engine overheat alert?
if temp of the cooling airflow exceeds a preset value
where is bleed air tapped from?
2 from HP. 7 and 12 compressor.
How is engine oil cooled?
fuel cooled oil cooler and filter.
How is IDG oil cooled?
passing it through a primary air cooled oil cooler located in the rear by pass duct. secondarily through a fuel cooled oil cooler
How is engine and IDG oil shared?
it cant
Where is starting air derived from?
APU, a ground supply unit or cross bleed from a running engine
Describe an engine start?
air is admitted to the starter motor when the electrically operated starter valve is open, when enegine selector is selected. the starter system is electrically armed and disarmed via the START pb. both fuel and ignition are applied when the respective fuel lover is opened. the starter motor rotates the HP shaft.
At47% starter cutout occurs. valve closes. if it doesn’t close a alert will be presented.
When should light up occur on starting?
after fuel introduction 20secs max
What are the starter limits?
4 attempts, max 2 mins, 30 seconds between. after 4, wait 15mins
What can you do if a starter valve doesn’t open?
Can be manually opened
What igniter plugs are active (and when) with the ignition selector in CONT 1 CONT 2 AUTO and relight?
cont 1, igniter 1 continuously
cont 2 igniter 2 continuously
Auto. igniter 1 , during start and when at 50kts wheel spin or reverse
relight, both continuously
How is ice prevented from forming in the engine fuel system?
via the fuel cooled oil cooler (heats the fuel)
What lever controls the HP fuel valve and what are its positions?
fuel lever. 2 positions. open and close.
By what means may the thrust levers be operated?
manually or ATS
What effect has the flight control lock on the thrust lever movement?
prevents selection of take off thrust with lock engaged, to approx 80% N2.
What thrust ratings may be selected on the TRP?
TOGA, FLX, CLB, CRZ, MCT
How do you set an assumed temperature for FLX?
by rotating the TEMP selector on TRP
What do you need to do to set EPR manually? (FLX)
same as temp y MAN EPR selector
How are thrust reverses actuated?
hydraulic system 1
How do you know reversers are operating?
a Green R is displayed at top of EPR tape.
Can thrust reversers be used before touch down?
no, on ground only
What happens if a reverser deploys inadvertently?
the corresponding thrust lever automatically retards to idle. REVERSER ENG 1 / 2 alert2
Where are engine indications are normally presented?
Primary page MFDU and secondary ENG page
What parameters does the EFSU look at?
Looks at thrust lever position and N1 to compare. Engine failure sensing unit. rapid loss of thrust
What is the SEI an when can it be used?
standby engine indicator. directly connected to the engines. can be used anytime with on of switch.
If only one MFDU is operating, how do you get the secondary page up?
XFR on MFDS panel
How is vibration indicated?
on secondary MFDS page, vib. outer N1, inner N2.
What do the normal and alternate vibration sensors monitor?
the engine spools.
