CH-47D Auxiliary Power Unit

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 1-1520-240-10 and the student handout

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

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

General Characteristics Model T-62T-2B Manufactured by Turbomach Consumes 90 PPH Rated Power 95 SHP Weight 74.8 W/O Generator Single stage centrifugal compressor/PT Mounted at Sta. 600 Above the ramp

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

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

APU Assembly

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

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

Air Inlet Section

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

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

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

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

APU Start Accumulator

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

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

APU Start Module

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

APU Motor/Pump

APU Fuel System

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

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

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

APU Fuel Control

APU Fuel Pump

Fuel Manifold Constructed: Metal fuel line Six bosses equally spaced

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

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

Magnetic Pickup

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

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

APU Oil System

APU Oil System

Oil Sump

Oil Pump

Oil Filter

Oil Filter Oil Pressure Switch

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

APU Fault Relay

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

BITE Information

New Modification (ESU)

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

Start Procedures

APU Control Switch

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

Master Caution/Advisory Panel

APU Operational Restriction

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

APU Fire Emergency Procedures APU switch – OFF. ABORT START. Pg: 9-1-22 Emergency Procedures APU switch – OFF. ABORT START.

Any Question?

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 2408-13 What is the maximum tailwind for starting the APU? 25 knots

Summary

Have a nice day and Safe Flying!

Engine Shutdown With APU or APU Generator Inoperative Page: 9-1-20