Engines Flashcards
What engines?
4x PW F117 -PW - 100 fly by wire turbofan engines
Dual Spool
Single fan stage
High bypass 6:1
Max flat rated thrust 40,440 pounds (at sear level)
Dual spool?
Referees to the compressor and turbine and shaft systems
Dual spool means to separate components
High pressure compressor and Turbine are connected separately to the low p C and T
Fire protection
The nacelles are isolated by a firewall in the middle wing pylons connecting the wings
Also two additional fire walls around the engine
N1 + N2
N1
- fan
- x4 comp
-X 5 low pressure turb
N2
- x12 height pressure comp
- x2 highl pressure turbine
6th-9th comp stage
Variable stator vanes
Allow variable amounts of air through
SVA stator Vain Actuator System
Combustion chamber
Singular annular burner
24 injections
How is the engine inlet anti iced?
Re circled bleed air
Advantages of an annular combustion
Uniform combustion
Better efficiency
Which stage and engine provides OBIGSS
14th stage inboard engines
Which states are responsible for bleed air
10-17th
EEC
Electronic engine control
After N2 = 10%
It is Powered by PMA - permenant magnet alternator
Dual channel A+B
Also can be Powred by DC bus engine bus
Loss of EEC
Degraded control state with slower accel and decel
What are the ECC modes?
EPR normal
N1 alternate primary - still good
N2 alternate - cannot control settings of N1 no ATS no reverse thrust. Engine limit protection is not available N2 must be monitored
Hung start
Engine normal combustion but does not accelerate to idle.
Airflow thought the system is insufficient
Could be caused by premature engine bleed
Max thrust ambient temp OAT
31 deg cel 87 far
@ SL
What does EGT margin give us?
EGT margin compares the EGT at max thrust compared with the 655 deg limit
655-645 = 10
This shows the current efficiency of the engine
When it decreases below 5 degrees it must be recored low EGT
Engine Thrust Ratings
Maximum
Intermediate
Max continuous thrust
De- rated
MAX
Limited to 5 mins for t/o
(10 for 3 engines)
T/o and GA
INT
Max thrust certified for continuous use
Only used if MCT isn’t sufficient
MCT
Max thrust used for normal climb operations. It is the max recommended power for four engine cruise
DRT
Min MC thrust required to safely perform take off
Less than MAX and equal to or greater than MCT
DRT with EPR limit No
DRT with EPR limit yes
DRT CAT II
When will Thrust Loss appear
When EPR of one engine is 0.15 less than the rest
Hung start parameters
Measure N2 every 10 seconds if it does now increase 1%
Sun idle hung start
Same as hung start but condition occurs for longer than 60 seconds after start button disengages
Engine Oil tank volume
28 Quarts
5 unusable
On display
Min 4
Max 23
Oil temp less than 50 deg
On t/o there will be a warning
Where is Eng oil temp sensor?
Downstream of the filter
2.5 and 14th Stage bleed on start?
To help prevent flame outs and surges
Engine cooling
Fan duct bleed air to the high pressure compressor
Fuel system
2 pumps
1 low pressure pump
- oil fuel heat Ex
- cools oil
- heats fuel
Fuel filter (with by pass valve)
2nd high pressure pump
Fuel control uni (FCU)
Master caution / fuel filter captions
Comes on when pressure across the filter reacher 5psi
Shut of valves
4 . One for each engine
Stops fuel at the FCU
Opening the valve also energies the engine ignition if selector at A or B
Ignition A and B power supply
A from the AC Emergancy BUS
B from the AC bus 1,2,3,4 (from the engines)
NORM/ORIDE
Located next to the ignition selector
Normal enables rotary ignition system. The ignition switch
ORIDE activities two over ride relays and and energises both A & B ignition systems on all 4.l engines and arms all 4 engine start buttons
Relay 1 power A for Eng 1,2 and B for 3,4
Relay 2 powers the opposite
Amber light on starter button
Indicated starter valve opens
Allows pneumatic pressure to rotate the Eng starter
Stays in until N2 52%
No.2 eng lightabove starter button?
Illuminates if there is a fire or if the fire handle has been pulled stays illuminated until the fuel shut of valve for the associated engine is turned
Reverse thrust operation
Blocker doors on both the fan duct and core duct
Move air out the top of the engine
Each system is operated by its own engine hydraulics
Thrust revers use in the air and on the ground? Slats?
Slats must be stowed in air and on the ground unless rejected takeoff or Landing
UNLK yellow message on MFD
Thrust reverse has started to deploy
When fully deployed will change to cyan and will read REV
MX THR TIME over/ rem
Over yellow counts up to 15mins
Green REM counts down from 5
FF PPH if it goes blank?
Fuel flow pounds per hour
Any of the four meters are inoperative
