1. CH-47D Auxiliary Power Unit

2. Terminal Learning Objective (TLO)
Action: Describe components, operational characteristics, functions, restrictions and limitations of the CH-47D Auxiliary Power Unit (APU)
Condition: In a classroom, given a student handout
Standard: Correctly answer in writing, without reference, three of four questions, pertaining to Components, Operational Characteristics , Limitations, Functions, and Malfunctions of the CH-47D APU, In Accordance With (IAW) TM and the student handout

3. Terminal Learning Objective (TLO) (Cont)
Safety Requirements: None
Risk Assessment: Low
Environmental Consideration: None
Evaluation: Each student will be evaluated on this block of instruction during the written examination. This will be a criterion type examination requiring a GO on each scored unit. You will have 90 minutes for the exam

4. Learning Step/Activity (LSA) #1
1. Describe operational characteristics, of the Auxiliary Power Unit (APU) Components

5. General Characteristics
Model T-62T-2B
Manufactured by Turbomach
Consumes 90 PPH
Rated Power 95 SHP
Weight W/O Generator
Single stage centrifugal compressor/PT
Mounted at Sta. 600 Above the ramp

6. APU Mounting Points Mounts: Two forward and two rigid links
APU to rotate down
Provide: Vertical and lateral support

7. APU System Components Motor/Pump APU Start Accumulator
APU Start Module
Motor/Pump
Auxiliary Power Unit
APU Fuel Shutoff Valve
APU Electronic Sequence Unit
APU Fuel Boost Pump
APU Fault Relay
Master Caution Panel
Overhead Panel
APU
Generator
Solenoid Valve

8. APU Assembly

9. Learning Step/Activity (LSA) #2
1. Describe Principles of Operational for the APU

10. Sections of the APU Power Turbine Assembly Reduction Drive Assembly
Air Inlet, and Compressor Assembly

11. Air Inlet Section

12. Compressor Section Type: Single stage centrifugal-flow (impeller)
Air drawn in through the inlet

13. Combustor Assembly Provides: Intake of ambient air to the compress
Protects: APU against FOD ingestion

15. Power Turbine Section Type: Impeller turbine rotor
Secured: Aft end of the turbine assembly

16. Reduction Gear Assembly
Purpose: Reduces power turbine shaft rotational speed
Three mounting pad

17. APU Start Accumulator

18. APU Start Accumulator Mounted: Sta.555 R/H Ramp Area
Purpose: Stores Hydraulic Fluid
APU Start
Emergency Use:
Utility Sub-System
Indicator: 3,000 PSI

19. APU Start Module Located: Directs: Controls: Indicator:
Sta.584 R/H side ramp area
Directs:
Signal Pressure
APU Accumulator
Controls:
Operating Mode:
APU Motor/Pump
Indicator:
3,000 PSI

20. APU Start Module

21. APU Motor/Pump Mounted: Forward Portion APU Function: Motor
Drives APU (Starting)
Pump
Supplies 3350 PSI
Engine Starters
Utility Sub-Systems

22. APU Motor/Pump

23. APU Fuel System

24. Airframe Mounted Fuel Boost Pump
Type: Rotary vane pump
Supplies: 7−40 PSI to the APU driven fuel pump
Energized:
APU start switch RUN position

25. APU Fuel solenoid Valve
Mounted: Boost pump
Normally closed, electrically opened valve
Purpose: Stops fuel flow to the APU

26. Pressure Fluid Filter Type: Paper filter element
Mounted: Top of the reduction drive assembly

27. APU Fuel Control

28. APU Fuel Pump

29. Fuel Manifold
Constructed: Metal fuel line
Six bosses equally spaced

30. Start Fuel Nozzle Assembly
Mounted: Combustor housing at approx. 7 O’clock position
Purpose: Sprays fuel directly in front of the spark plug

31. APU Electrical System Battery Switch Two position APU Switch
Three position
APU GEN switch

33. Magnetic Pickup

34. Ignition Exciter Box Mounted: Upper R/H side of the turbine
Purpose: Convert DC input to high energy AC

36. Event/Time Meter Purpose: Tracks starts on the rotor assembly
Tracks APU operational time

37. APU Oil System

38. APU Oil System

39. Oil Sump

40. Oil Pump

41. Oil Filter

42. Oil Filter Oil Pressure Switch

43. Manual Shutoff Valve Located: Sta.540 L/H side of ramp area
Purpose: Shut down the APU during an emergency

44. APU Fault Relay

45. Electronic Sequence Unit (ESU)
Located: Sta.585 L/H side
Purpose:
Sequences the start procedure of the APU
Continuously monitors the APU operation
Contains: Four BITE latches for fault indications

46. BITE Information

47. New Modification (ESU)

48. Learning Step/Activity (LSA) #3
1. Describe Start Procedures, Operational Restrictions and Emergency Procedures of the APU

49. Start Procedures

50. APU Control Switch

51. Start Procedures Three Positions Switch
Off
Run
Start
Place switch to RUN for 3-5 seconds
Move switch to START for 2 seconds and release to RUN

52. Master Caution/Advisory Panel

53. APU Operational Restriction

54. Tail in the wind!!! APU Exhaust
The APU shall not be started with a tail wind in excess of 25 knots

55. APU Fire Emergency Procedures APU switch – OFF. ABORT START.
Pg:
Emergency Procedures
APU switch – OFF.
ABORT START.

56. Any Question?

57. Check On Learning What two components are driven by the APU?
Motor/Pump and Generator
How long should you wait before attempting a restart on the APU?
1 Minute
If the APU ON caution light fails to comes ON, what should you do?
Record the BITE information on
What is the maximum tailwind for starting the APU?
25 knots

58. Summary

59. Have a nice day and Safe Flying!

60. Engine Shutdown With APU or APU Generator Inoperative
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