Engines Flashcards
What percentage value passes through the core of the engine?
52%, the other 48% is around the engine.
What is the purpose of the Anti-Surge Bleed System is it automatic?
It is automatic.
Prevent compressor stall during initial acceleration
Air in acceleration of the engine rotor during start.
Which compressor is the low compressor and how many stages does it have?
N1 and it comprises the first 6 compressor stages.
Which compressor is the high compressor stage and how many stages does it have?
N2 and it comprises the last 7 compressor stages.
What is the Starter Duty Cycle?
90 seconds ON, 5 min OFF, 30 seconds ON, 5 min off. (May continue indefinetely).
What is the Ignition Duty Cycle?
10 minutes ON, 10 minutes OFF.
Losing N2 RPM sense input to the Fuel Control will cause what engine reaction?
The engine will default to takeoff RPM.
Losing Ps4 input to the Fuel Control will cause what engine reaction?
The engine will default to idle RPM.
What can be done to help cool hot engine oil, if still within limits?
Increase thrust. This will move colder fuel at a fast rate through the fuel oil cooler.
The start valve solenoid is powered by what bus?
The DC Transfer Bus through the ENGINE START switch.
Which engine instruments do not require electrical power?
N1
N2
EGT
Which engine compressor section drives the accessory gearbox and how is this achieved?
N2, and this is done through a tower shaft.
What accesories are mounted on the gearbox?
Pneumatic Starter Engine driven fuel pump Fuel control unit Hydraulic pump Tachometer generator Oil pump Constant Speed Drive (CSD) AC Generator
What is the recommended psi for a start and can an attempt with a lower value be made?
36 psi and yes you may attempt with a lower value.
How many gallons of oil are in the engine oil tank and how many are usable.
5 total 4 of which are usable.
Can an oil strainer be bypassed?
Yes. But you would see an oil strainer clogging light go on.
How is oil cooled?
With airflow and by fuel absorbing heat in the fuel oil cooler unit.
What psi does the low pressure engine driven fuel pump pressurize fuel to?
90 psi
What psi does the high pressure engine driven fuel pump pressurize fuel to?
900 psi
What is the path that fuel takes from the wings to the engines?
Low pressure fuel pump (90 psi) Fuel heater Fuel filter High pressure pump (900 psi) Fuel control unit Fuel oil cooler Combustion chamber
Can the high pressure pump suction feed?
No, only the low pressure pump can.
If the low pressure pump fails what engine operation is affected?
Fuel heating will not be operable.
Can the engine run with the high pressure fuel pump broken?
No the engine will flameout due to fuel starvation.
Where does the fuel filter get its air from?
The 13th stage bleed air. (Off its own manifold).
Where does the Fuel Control Unit get its indications from?
N2
Inlet temperature (Tt2)
Combustion chamber pressure (Ps4)
Thrust lever settings
Hos is the Fuel Control Unit driven?
By N2 off the engine accessory drive.
What will happen if N2 sense is lost?
The engine will automatically drive to 95%. Throttle control will be lost.
If the combustion chamber air pressure line ruptures what will happen to the engine?
It will be driven to idle RPM. Throttle control will be lost.
What is the capacitance of the engine ignition system?
20 Joules
When will the ignitors function?
When selected to either A or B and the fuel control levers ON.
Are thrust reversers considered to be part of the landing criteria?
No
What powers the RAT/EPR probe?
Right AC Bus
Is that RAT/EPR probe heated?
Yes inflight only sensed groundshift.
What does Automatic Reserve Thrust do and what does it look for? (MD80)
Compares engine N1 rotation against one another looking for a difference of 30%. Will increase thrust on the good engine by 700 lbs.
What are the three things that will cause ART to fire?
30% difference in engine N1
Windshear
Switching flight guidance systems
What is the max thrust of JT8D-219 engines? (MD80)
21,000 lbs.
What is the max start EGT for JT8D-219 engines? (MD80)
475 on the ground and 625 inflight.
What is max continuous EGT for JT8D-219 engines? (MD80)
580
What is max takeoff EGT for JT8D-219 engines? Is there a limit associated with this?
630 Reserve, 595 max. Has a limitation of 5 minutes.
When does ART arm?
When both engines are above 64%
What does Automatic Thrust Restoration do and when is it activated?
It will move both throttles up until one engine reaches its EPR limit. It is activated by vertical speed < 0 for 5 seconds or there is a .25 and 7% N1 drop on the same engine.
When is Automatic Thrust Restoration armed?
Takeoff pitch selected in the flight directors
Altitude is > 350 ft.
Power is less than that for GA in both engines
When does ART know when to engage?
By comparing N1 rotation and looking for differences that are greater than 30%.
When does ART disarm?
When the slats are retracted,
