Engine Flashcards
Describe the 787 Engines
GEnx 1B67 or 1B74/75
67,000 74/75,000lbs thrust rating
Dual rotor axial flow turbofans of high compression and bypas ratio
Where is the Engine Accessory gear box
N2
What is on the Accessory gear box
FWD
heat exchanger
HYD pump
lube and scavange pump
PMA
AFT
Starter Gen
fuel pump
FMU
flow split valve
How is Reverse thrust provided
Cascading vane system
provides reversal of only the fan airflow while engines primary airflow continues normally
What is the EEC
What does it do?
Electric Engine Controller
monitors the thrust lever position and controls the eng and provides limit protection
What does the Fuel Cutoff switch do
Closes the Engine Fuel Valve
removes ignitor power
unlocks Engine Fire Switch
When is the Engine Fire Switch automattically unlocked
no power on the aircraft
fuel control switch is in CUTOFF
A Fire is Detected
What happens when you pull a Engine Fire Switch
Arms both Extinguishers Closes Spar Fuel valve Closes engine anti ice Engine Generators off line Cuts HYD fluid Cuts power to thrust reversers
What does the START switch do
opens the Spar Fuel Valve
Starter motor energizes
When does the In Flight Start envelope display on the EICAS
Fire Switch not pulled out
and
Fuel control in cut off
or
Engine is not running in flight
What does X Start below N2 on the engine display mean
altitude or airspeed is below outside the displayed windmilling envelope
What is the EGT inhibit times and where does this occur
Inhibited from changing amber during takeoff or Go-around for 5 min
What is the only thing that will stop an engine airstart once it has been started
Fuel Control switch - CUTOFF
What do the starter motors drive
the N2 via the accessory gear box
What are the sources of power for eng start
Ext
Engine
APU
What is the preferred method of starting the engines
Simultaneous
In order to get the benefit of the AFT EXT AC power for engine starts without APU what has to happen
Start the right engine first
On the ground how many Auto start attempt will be made
3
What is eng roll back
Sub idle stall
N2 falls below Idle
What does the EEC do when a Flameout is detected
Dual ignitors
What valves close when either the Engine Fire switch is pulled or Fuel Control Switch is in CUTOFF
Spar and Engine Fuel Valves close
What is the sequence of travel of fuel to the eng
Fuel spar First stage pump Oil heater second stage pump fuel filter FMU Eng fuel valve engine
Where is Fuel Flow from the ED taken
passing through the Engine fuel valve
right before the eng
What drives the Eng Oil system
N2 power
Engine Acessory Gear box
Where is oil temp and press taken
prior to oil entering the eng
What is engine oil “gulping”
During the start sequence oil quantity may drop several qrts
Is there a minimum Oil QTY in flight
no
Which device provides control over thrust reverse operation
EEC
What actions occur when Reverse Thrust is selected for T/O or Ldg
Autothrottles disengage
Speed brakes Deploy
When in EEC Alternate Mode what do you have to remember
Maximum thrust is reached a thrust lever position less than full fwd
What does EICAS - ENG RPM LIMITED R mean
EEC has recognized a N2 at the red line limit
it reduces fuel flow to control the overspeed
What are the Idles set by EEC
Min idle
Icing Idle
Approach idle - Flap > 25, or Gear Down
What are the Idles set by EEC
Min idle
EAI -Icing Idle
Approach idle - Flap > 25, or Gear Down
What is Approach idle
decreases acceleration time for Go-Around
When is EAI selected
When eng anti ice is on
What is thrust ramping
EEC slowly increases thrust to protect fan blades in high wind situations.
Max thrust available at 65 kts
What is thrust control malfunction Accommodation
protection against thrust asymmetry conditions on the ground for landing
on ground at idle if not decelerating normally.
What is TAP
Thrust asymmerty protection
protection against asymmetric thrust during T/O of GA
allows for a decrease in approach speeds at lower WTs
How does TAP help with OEI operations
reduces thrust on operating eng to allow sufficient rudder control
(T/O decreases thrust if below V2
GA decreases thrust if below Vref)
How can TAP reducing thrust if below V2 or Vref help
the thrust asymmetry creates more drag than the thrust adds
resulting in a high climb gradient
What is the TBV
Transient Bleed Valve
Unloads the compressor during eng acceleration in order to increase the eng stall margin
Where is eng vibration detected
N1 or N2 (will say on EICAS desplay)
BB - Broad band Vibration gives an average
(primarily for Rotor imbalance)
What is the limit of vibration
4 units
When do you get a time critical WARNING Eng Fail
Actual thrust is less than commanded thrust during T/O with airspeed between 6 - 65 kts
Which spool are you more likely to feel a tactile vibration
N1
