Engine Flashcards
How are pilot commands translated to engine response?
-1 Section 1
Functionality
Through the PAS and LDS inputs to the HMU. They are connected to the PCLs and the Collective respectively.
What is the primary function of the EDECU?
-1 Section 1
Functionality
- Provide Q matching/load sharing
- TGT limiting
- NP governing
- NP overspeed protection (sensing)
- HSP (sensing)
How does the oil system work?
-1 Section 1
Functionality
Oil is kept in reservoirs and bleeds slowly out of those reservoirs to be atomized by air jets, providing continuous oil mist lubrication for the bearings.
What feature is implemented to help the oil in cold weather?
-1 Section 1
Functionality
An impending bypass indicator has a thermal lockout below 38 degrees C to prevent the button from popping in cold weather.
What is the “I’m a drop of fuel” flow?
-1 Section 1 (chart)
Physical Orientation
From the tanks (duh)
Engine driven suction pump
Fuel pressure sensor
Fuel filter
HMU
Oil Cooler
ODV
Fuel injectors
Why do we care about the kind of pump that the engine uses for fuel?
-1 Section 1
Functionality
It’s a low pressure suction engine driven boost pump which assures that the airframe fuel supply system is under negative pressure, thus lessening the potential of fire in case of fuel system damage.
What is really causing filter buttons to pop?
-1 Section 1
Functionality
Pressure differential
What is the HMU’s job?
-1 Section 1
Functionality
Control the fuel to ODV for combustion
What does the HMU do?
-1 Section 1
Functionality
Pumps fuel at high pressure
Meters fuel to the ODV (fuel flow)
Positions AISBV
Positions variable guide vanes
What does the ODV do?
-1 Section 1
Functionality
Purges fuel on shutdown
Primes fuel on startup
Shuts of fuel in NP overspeed sensed by EDECU
Shuts of fuel if hot start sensed by EDECU
How does the starter disengaged? What does this prevent? On a normal start
-1 Section 1
Functionality
It has an overrunning clutch which disconnects the starter output shaft from the gear box when the gear box speed exceeds the starter’s speed.
It prevents the starter from being driven by the engine.
How can we manually disengage the starter?
-1 Section 1
Functionality
Pull down on the PCL
Hoe do you abort a start?
-1 Section 1
- Pull down on the PCL
- Press the secondary latch release
- Move PCL to OFF
What do you do if we accidnetlaly tried to start with the ignition keylock OFF?
-1 Section 1
- Do not turn the keylock ON after motoring has started (to prevent a hot start)
- Abort start procedures
Can we do a dual engine start with the APU?
-1 Section V
OpsLimits
Yes, there’s a chart for that though. It depends on the OAT and PA.
What is required for a crossbleed start?
-1 Section 2
Checklist
- NG at least 90%
- Air source heat/start to ENG
- NR 100%
- ENG ANTI-ICE ON advisory for the donor engine out
Describe the air ports/valves during a crossbleed start
-1 Section 1
Functionality
When the air source heat start switch is placed to ENG- both engine crossbleed valves will open (45 degree ones)
When the starter button is pressed the receiving engine’s start valve will open and the crossbleed valve will close.
The donor engine’s crossbleed valve is obviously open but it doesn’t explicitly state it
What if our APU Gen doesn’t work, and we don’t have external power, can we still start?
-1 Section 1
Functionality
Yes.
It is possible to start the No 1 engine using only battery and either an external air source or an APU with an inoperative APU gen.
This procedure is not recommened (lol)
If we don’t have AC power but we do have external air source which engine will we start first?
-1 Section 1
Functionality
No. 1
Because only the No 1 engine start control valve can receive power from the battery via the DC essential bus.
What does the alternator do?
-1 Section 1
Functionality
- supplies power to ignition exciter
- power to EDECU
- NG signal to cockpit
What failsafe is built into the EDECU in the case of alternator failure?
-1 Section 1
Functionality
Helicopter power (400 Hz 120 VAC) is utilized to prevent engine high side failure.
What is still available if the alternator fails?
-1 Section 1
EPs
NP overspeed protection.
How will an engine alternator failure present itself?
-1 Section 1
EPs
Loss of NG signal in cockpit and activation of the NEG OUT warning and audio.
ALL OTHER ENGINE INDICATORS WILL BE FINE.
What is the TGT bias that the EDECU incorporates?
-1 Section 1
-112 degrees
So the displayed TGT is 112 degrees (+/-13) lower than actual. Why does it have this? no one knows, good luck
How do you know the DAS plug is installed?
-1 Section 1
You’ll see a Q code of 25% +/-3% initially displayed for 20 seconds.
What are some ways we can access the single engine 2.5 minute TGT limiting?
-1 Section 1 AND Section A (sneaky sneaky)
Functionality
- EDECU Lockout (lol gotcha)
- One engine’s Q is <50%
- NP droops below 96%
- > 3% per second droop between reference NP and actual NP
- > 5% per second droop rate exists and NP is less than or equal to reference NP
What is reference NP? Why do we care?
-1 Section 1
96.5-100.5
It’s what the EDECU uses for controlling NP on both engines.
What is our NP Overspeed?
-1 Section 1
120+/-1%
What is not deactivated in Lockout?
-1 Section 1
It’s a WARNING, EDECU lockout does not remove max fuel flow or NG limiting.
What are the two sensors on the rear of the engine sensing?
-1 Section 1
(left to right)
NP and Q sensor
Overspeed sensor
Maybe…PDf 168 is confusing
