Systems 2 - Engines Flashcards
There are two components to control the engines. The specific engine either has a _____ og an _____?
DEC , EDECU
DAS is short for?
Discrete Application Selection plug
Regarding the Tempaerature tape on the engine, _____ is good, ____ is bad
2 , 3
HMU is short for:
Hydro Mechanical Unit
PAS is short for:
Power Available Spindle
LDS is short for:
Load Demand spindle
What is the purpose of DEC/EDECU?
Limit the pilots load by:
(a) Maintaining a constant power turbine speed of 100%.
(b) Turbine Gas Temperature limiting, (limits the TGT to 879°C ± 9° or 903°C ± 10°)
(c) Load sharing (which keeps the torques of both engines matched within 5%),
(d) Power turbine overspeed protection (limits the power turbine speed to 120 ±1%)
HSP is short for? - And what does it do?
Hot start Preventer
Shuts down the engine in case of temperature getting to high during start up
What is the HMU?
A fuel control unit, controls fuel to the combustion system.
What is the funtion of the PAS?
The spindle changes linear cable movements into rotary inputs for the HMU
What is the function of the LDS?
This mechanical link between the collective and the HMU makes fuel-scheduling adjustments in a proactive attempt to match engine power to rotor load.
The function of Power takeoff drive assembly
The power takeoff drive assembly drives a radial drive shaft that mechanically links the accessory gear box and NG.
IGV is short for:
Inlet Guide Vane
What is the function of the IGV?
Control the amount of air entering the engine
VG is short for:
Variable Geometry
What is the function of the VG aid in acceleration and prevent compressor stalls VG?
Aids in acceleration and prevent compressor stalls.
IPS is short for:
Inlet Particle Separator
LRU is short for:
Line Replaceable Units
“Any part that can be removed and replaced at unit level maintenance (AVUM) with another like part like:”
(a) Oil filter
(b) Oil pump
(c) Liquid to liquid cooler
(d) Fuel filter
(e) Alternator
ODV is short for:
Overspeed Drain valve
What is the function of the ODV?
Controls the fuel flow into the engines.
Reacts by shutting of fuel flow during an overspeed or hot start
The ENG POWER CONT lever is mechanically linked to the _____ through a cable.
The ENG POWER CONT lever is mechanically linked to the Power Available Spindle (PAS) through a cable.
What is theEngine Inlet Temperature (T2) used for?
(1) T2 is used by the HMU to compensate for changes in air temperature.
(2) Inlet air temperature information from the T2 sensor is also used for NG limiting.
NG is short for:
Gas Generator Speed
NP is short for:
Power Turbine Speed
Q is short for:
Torque
What section of the engine mechanically drives NR?
NP section
Is the NG section mechanically connected to NP?
No
What is the connection of NP and NR?
One-way mechanical connection via the freewheeling unit
Name the four modules of the T700-GE-701D engine
Cold, hot, power turbine, accessory gear box
What drives the accessory gear box?
Gas Generator (at a variable speed)
How many stages are there in the compressor section (NG)?
There are 6: 5 axial and 1 centrifugal
What are the two operational sections of the engine?
NG and NP
If flights of over six hours are made, engine oil level MUST be at the _____ of sight glass before flight.
Full Line
How does engine oil cooling occur?
Liquid to liquid cooler, oil flow through the 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
3 important function of the DEC
TGT limiting
NP governing
Q load share
How does the DEC decide which parameter is the limiting factor?
The limit that wants the least fuel (normaly the govenor)
Where does the engine receive its electrical power?
Engine alternator
How does the cockpit receive the NG signal?
From the NG winding of the alternator.
If you go to lockout on the Pwr Cont Lever, what limiting do you lose?
Tgt limiting
NP governing
Q load share
When in lockout what limits do you still have?
Np overspeed protection
Hot start prevention
Green cables in the engine sends _____
Signals to the cockpit
If NG signal is lost, what happens?
ENG OUT warning light and audio, and 0% NG.
Why does the fuel system operate on negative pressure?
It assures that the airframe fuel supply system is under negative pressure, lessening the potential of fire in case of fuel system damage
What happens when the fuel filter clogs?
Bypass indicator pops out, bypass valve opens
How does the engine compensate for variable power demands from collective inputs?
The LDS increases/decreases fuel flow
How is engine power adjusted with the PCLs in lockout?
Adjustment of the engine power control levers adjusts the PAS to set the maximum power available
Is the APU capable of starting both engines simultaneously?
Yes, within certain ambient temperature ranges
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% and above
How do you manually disengaged the starter?
You must pull down on the PCL to disengage the starter
If alternator power is lost to the engine, will the DEC still remain functional?
Yes, it is also supplied from the AC airframe power
What does the HSP automatically prevent?
It prevents over temperature during engine starts by shutting down the engine
What system keeps the engines at an approximate equal torque?
The 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°C to 13°C it may or may not activate, <4°C it must activate
With engine anti ice activated how much should maximum Q available be reduced?
-20%. With cockpit gunner heater on reduce another 5%
What do you do if you encounter a single engine failure during flight?
Collective — Adjust to maintain NR
External cargo/stores — Jettison (if required).
Establish single-engine airspeed.
If continued flight is not possible
LAND AS SOON AS POSSIBLE
If continued flight is possible:
LAND AS SOON AS PRACTICABLE
How do you recognize an engine compressor stall?
A loud banging or popping accompanied by rapid increase in TGT and fluctuations in NG, Q, and NP
Engine start abort criteria:
- No TGT increase (light off) within 45 sec
- No P (eng oil pressure) within 45 sec
- No NP1 or NP2 within 45 seconds (if rotor brake is off)
- ENG STARTER ON caution disappears before reaching 52% NG.
- TGT reaches 851°C before idle is attained (above 63% NG).
CAUTION: If start is attempted with ENGINE IGNITION switch _____, do not place switch to _____. Abort the start.
OFF , ON
When turning the engine Inlet anti ice on, at _____ degrees the the anti ice must turn on.
Between _____ degrees and ______, it might turn on or might not.
Over _____ degrees, it must stay off.
When turning the engine Inlet anti ice on, at 4*C the the anti ice must turn on.
Between 4*C degrees and 13*C, it might turn on or might not.
Over 13*C degrees, it must stay off.
UES is short for
Upturned Exhaust system
Eng anti ice is required to be off above ____% and on below _____ %
92% , 88%
