Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MH-60R HAC HSM-50 > NATOPS Chapter 2 Engine Control System HSM-50 > Flashcards

NATOPS Chapter 2 Engine Control System HSM-50 Flashcards

1
Q

System purpose

A

Maintaining constant Np/Nr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Major components of the Engine Control System

A 
HMU
ODV
EDECU
Engine-driven Alternator
Series of fuel flow control valves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

System is governed through

A

Interaction of DECU and HMU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

HMU vs EDECU functions

A

HMU provides gas generator control

DECU trims HMU to satisfy requirements of power turbine load and reduce pilot workload

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

PCL positions

OFF - IDLE - FLY - LOCKOUT

A

Off - PAS mechanically shuts off fuel at shutoff valve within HMU
Idle - HMU auto controls start sequence fuel flow allowing engine to get to self sustaining combustion
Fly - provides max level of power if necessary
Lockout - PCL manually controls Ng and Np

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do you lose and retain in lockout?

A

Retain - Np overspeed system via manual connection between DECU and ODV
Lose - TGT limiting, Np governing, load sharing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How far can you move PCL with rotor brake applied?

A

IDLE; solenoid activates locking device that prevents it from moving further

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Collective is to __ as PCL is to ___

A

Load Demand Spindle (LDS); Power Available Spindle (PAS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where is engine driven fuel boost pump mounted?

A

Fwd side of AGB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

2 Purposes of the Engine Driven Fuel Boost Pump

A
  1. Provide reliable suction feed from fuel tank to engine (minimize vulnerability/fire hazard if fuel lines damaged)
  2. Provide discharge pressure to satisfy minimum inlet px req of HMU or high px fuel pump
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Does the Engine Fuel Filter filter water?

A

No; solids only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Activation of #1/#2 FUEL FLTR BYPASS

A

Afte electrical switch senses pressure difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

HMU receives filtered fuel through

A

Cored passage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

HMU stands for

A

Hydromechanical Control Unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

HMU contains

A

Fuel stuff:High px fuel pump, Ng gov, metering valve, shutoff valve

Control stuff: LVDT, torque motor servo

Anti ice stuff: variable geometry vane servo

And this: vapor vent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Inputs to HMU

A

2 mechanical, one electrical

17
Q

First mechanical input to HMU

A

from LDS; directly coordinates Ng speeds to approx power required by rotor system based on collective position

18
Q

Second mechanical input to HMU

A

through PCL; PCL position manipulates PAS at HMU to set desired power setting

19
Q

Electrical Signal to HMU

A

from DECU; actuates torque motor servo in HMU to precisely trim Ng speed for power turbine control and load sharing

20
Q

HMU responds to PCL for

A
  1. Fuel Shutoff
  2. Setting engine start fuel flow with automatic acceleration to ground idle
  3. Setting permissible Ng up to maximum
  4. Fuel priming
  5. DECU override capability (LOCKOUT)
21
Q

3 signals HMU responds to and what for

A

T2, P3, Ng; signals aid HMU in controlling variable stator vanes and anti-ice/start bleed valve position during engine start and normal ops, reducing chance of compressor stall

22
Q

Fuel flow through HMU

A

fuel flows to HMU via cored passage –> high px engine-driven pump –> metering valve and shutoff valve –> external line to oil to fuel heat exchanger; some fuel goes to metering valve, servo piston, and various signals (T2, P3, Ng). see 2-8

23
Q

Why actual level of engine power is normally more than req by helo

A
  1. Fail safe to high power - prevent being power limited if have engine electrical failure
24
Q

What is lockout actually doing?

A

disabling the torque motor servo

25
Q

Failure to clear EDECU fault codes will prevent

A

AFCS Ground Checks & Blade fold

26
Q

EDECU Functions

A

4N CHEF TASTEE

Np governing
Np overspeed
Np overspeed test
Ng decay relight feature

C Power (MAD: Manual, Automatic, Dual Engine Auto)
Hot Start Prevention
Engine Load Sharing
Fault diagnostic System

TGT Limiting
Auto ignition system
Signals (Cockpit)
Transient Droop Improvement
EDECU Lockout
Engine Speed Trim

27
Q

Never reset a popped ENG OVSP CB because

A

it may initiate engine overspeed signal and cause the engine to fail

28
Q

TGT Limiting

A

Reaching either MRP or CRP functions w/in the EDECU

Fuel flow limited at 878C

Droops Nr at 866 ± 10C

29
Q

Ng decay relight feature

A

If an engine flames out and Ng decay exceeds a certain rate

Auto relight comes on for 5 sec

Disabled below 62%

30
Q

Manual C power

A

TGT can increase to 903

max CRP limiter will prevent further increase in fuel flow to engine at 891 ± 10

31
Q

Auto C power

A

enabled in OEI conditions

when tq from oen engine <50%, opposite engine EDECU will auto reset TGT limiter to 891±10°

32
Q

Dual Auto C power

A

bring TGT limit to 891±10°

To activate, one or more must exist:

  1. Np drops below 96%
  2. Greater than 3% droop between reference Np and actual Np
  3. Greater than 5% per second Np droop rate exists with Np less than or equal to Np ref set point
33
Q

Control parameters of EDECU?

A

Np sensing, Np overspeed and tq sensing, TGT monitoring

34
Q

EDECU receives these inputs from the cockpit

A
  1. Engine speed trim switch
  2. C power switch
  3. Engine over speed TEST A and B
35
Q

Np Overspeed Test

Description and what to do for flameouts

A

Rereferences Np Governer from 120% to 96%

Successful test: Ng decreases w/ both buttons pressed

If 1 button is pressed and Ng decreases: indicates a failed button

If engine flames out after a test:

Do a normal start of the engine
Bring opposite engine to Idle
Retest the engine that flamed out

If it relights: Fly-Fly good to go

If it flames out again: advance opposite PCL to Fly
Have Mx Check (can only retry once)

36
Q

Important EDECU Fault Codes

A

15: EDECU failure (will cause high side if you start up)

35: CEDECU installed w/ correct software

If you need to clear code: do EDECU fault code clearing procedure

37
Q

What does a CEDECU provide that an EDECU does not

A

Discrete Application Selection Plug (specific software for the Romeo instead of the other A/C series) (35% displayed as EDECU code)

MH-60R HAC HSM-50 (73 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions