Powerplant Flashcards
What are the positions on the PCL?
OFF, IDLE, FLY, LOCKOUT
What does HMU stand for?
Hydromechanical Unit
What section of the engine mechanically drives RPM R?
Np section
How is the Ng section connected to Np?
By (expanding, burning) gasses. (Not mechanically)
What is the connection between Np and RPM R?
One-way mechanical connection, via the free-wheeling unit
Name the four modules of the T700-GE-701D/CC engine
COLD, HOT, power turbine, accessory gear box
What drives the accessory gear box?
Gas generator (Ng, at variable speed)
How many stages are there in the compressor section (Ng)?
6: 5 axial, 1 centrifugal
What are the two operational sections of the engine?
Ng and Np
How does the engine oil cooling occur?
Liquid to Liquid cooler and oil flow through scroll vanes.
What is the service capacity for the engine oil?
7 quarts
Where is the oil drawn from for the emergency oil system?
Sumps A and B
How does the oil system overcome high pressure during cold starts?
Oil filter bypass valve, liquid to liquid cooler bypass valve.
Which component provides electrical power to the engine?
Engine alternator
How does the cockpit receive the Ng signal?
From the Ng winding of the alternator
What happens if Ng signal is lost?
ENG OUT warning light and audio 0% Ng read out on the PDU
Why does the fuel system operate on negative pressure?
It lessens the potential of fire in case of fuel system damage, by assuring that the airframe fuel supply system is under negative pressure.
What happens when the fuel filter clogs?
Bypass indicator pops out, and the bypass valve opens.
How does the engine compensate for variable power demands from collective inputs?
The LDS (Load Demand system) increases/decreases fuel flow
How is engine power adjusted with the ENG POWER CONT levers in lockout?
Adjustment of the EPCLs adjusts the PAS (Power Available Spindle) to set the maximum power available.
What is LDS an acronym for?
Load Demand System
What is DEC an acronym for?
Digital Electronic Control
Is the APU capable of starting both engines simultaneously?
Yes, with certain ambient temperature ranges. (Not recommended)
At what Ng should the starter caution disappear?
52-65% Ng
With one engine operating, what Ng must be maintained to crossbleed start the other?
≥ 90%
How do you normally disengage the starter?
Pull down on the EPCL to disengage starter.
If alternator power is lost to the engine, will the DEC/EDECU still remain functional?
Yes, it is also supplied from the AC airframe power
What does the HSP automatically prevent?
Over-temperature during engine starts by shutting down the engine.
What system keeps the engines at an approximate equal torque?
Torque matching/load sharing system
Other than bleed air, what is used to assist in engine anti-ice functions?
The hot engine oil also provides a passive anti-ice function.
The engine inlet anti-ice automatically activates between what temperature ranges?
4 to 13 degrees Celcius may or may not activate above 4 degrees it must activate
701D/CC with engine anti-ice activated, how much should maximum %TRQ available be reduced?
18%, with cockpit gunner heater on reduce further 4%
What is the purpose of the HIRSS system?
To reduce line of sight heat signature of the hot engine surfaces.
How do you recognize an engine compressor stall?
Noticeable bang or popping noise and possible helicopter yaw.
How many SHP does the T700-GE-701D/CC Engine produce?
1760
What are the functions of the HMU?
- Controls fuel to the combustion section - Contains a high pressure valve that delivers fuel to the Overspeed and Drain Valve (ODV)
The load demand system supplies what?
A mechanical and electrical signal to the load demand spindle on the engine HMU fuel control through a push pull control.
