What engines are on the airplane?
Pratt & Whitney of Canada JT15D-4
What do stator vanes do?
Help direct incoming air into and around the engine
How much thrust goes through the primary, inner path of the engine?
How much of the air going through the primary, inner path in the engine is used to drive the fan, and how much is exhaust?
A little less than half to drive the fan, a little more than half is exhaust.
How much of the engine's thrust comes from the secondary, outer path?
How much total thrust does each engine produce?
What is the bypass ratio?
2.7 to 1
Explain the bypass ratio.
About 78 lbs of air per second goes through the engine.
About 56 lbs of that goes around the engine's core.
Only 21 lbs goes through the engine's core.
So for every 1 lb of air that goes through the core, 2.7 lbs goes around the core.
What are the six engine sections?
- -Low compressor section
- -High compressor section
- -Combustion section
- -High turbine section
- -Low turbine section
- -Accessory gear box
How is ITT derived?
From 8 probes.
T2 probe sticks out in front of the fan, T2.6 probe is in the exhaust nozzle.
There are 6 other probes in the hot section.
Together, they send the T1 temperature value to the ITT gauge.
What six things are in the accessory gearbox?
- 1. Starter Generator
- 2. Engine-Driven Fuel Pump
- 3. Hydraulic Pump
- 4. Oil Pump
- 5. N2 Tach Generator
- 6. Two Vertical Tower Shafts
How does a Fuel Control Unit work?
It uses flyweights and needles to let fuel through to the engine in response to throttle movements.
What does the Oil-To-Fuel Heat Exchanger do?
It transfers heat from the oil to the fuel.
The problem is that this takes place AFTER the fuel filter, so if you have ice in the fuel the whole system can clog at the filter before it has a chance to heat up.
After you shut down the engine, you notice fuel dripping out of it onto the tarmac.
Is this a problem?
No. The flow divider dumps unused fuel overboard after engine shut-down.
What causes the green lights above the ignition switches to go on?
They go on when electrical power is supplied to the ignition system.
How much oil does each engine hold?
2.08 gallons, of which 1.25 gallons is usable.
When does automatic fuel shutoff happen?
If the N2 shaft displaces 0.07 inches rearward, or if the #4 bearing in the Accessory Gearbox fails.
What is the N1 limit?
Do the N1 tapes require electrical power?
No, they're self-generating above 50%.
So you can lose electrical power and still have engine power indication.
What ITT should a normal engine start not exceed?
How long can the ITT gauge read 700 degrees before you must terminate the start?
What is the N2 limit?
What three starting problems should cause you to terminate the start sequence?
No N1 by the time N2 is at 25%
ITT 700 for 2 seconds
What is the starter disengage sequence
Throttle off for 15 seconds
Then press the disengage button