UH-60A UH-60L EH-60A HH-60A HH-60L Aviation Unit Intermediate Maintenance Troubleshooting Manual TM 1-1520-237-23-2 Volume 2

Description

File Details

• Manual type: Aviation Unit and Intermediate Maintenance Manual (troubleshooting procedures, Volume 2)
• Document number: TM 1-1520-237-23-2
• Brand / models: U.S. Army utility tactical transport helicopters UH-60A NSN 1520-01-035-0266 (EIC:RSA), UH-60L NSN 1520-01-298-4532 (EIC:RSM), EH-60A NSN 1520-01-082-0686 (EIC:RSB), HH-60A NSN 1520-01-459-9468 (EIC:RSN), HH-60L NSN 1520-01-471-6743 (EIC:RSI)
• Language: English
• Page count: 1087
• File format: PDF
• Publication date: 30 May 2014 (Headquarters, Department of the Army)
• Noted change marking: Change 5, 31 March 2014 on selected work packages
• PIN: 073172-000

What This Volume Covers

The UH-60A UH-60L EH-60A HH-60A HH-60L Aviation Unit Intermediate Maintenance Troubleshooting Manual TM 1-1520-237-23-2 Volume 2 is the Chapter 2 troubleshooting book for Army utility tactical transport helicopters. It is not a full multi-volume remove-and-replace set. Work packages walk a unit or intermediate technician from an operational checkout through symptoms, malfunctions, voltage and continuity checks, linkage inspections, and corrective actions that point to a follow-on work package or to engine TM 1-2840-248-23 when the airframe is cleared.

Model-specific callouts appear throughout. IVHMS paths are written for UH-60A and UH-60L. Multifunction display caution and advisory grids are written for HH-60A and HH-60L. EDECU warnings apply to H60A/L aircraft that must not have the Discrete Application Selection plug installed. Central display units, signal data converters, and caution/advisory panels are split by part number so the correct AVIM bench procedure is used.

Chapters Covered

Volume 2 opens with the warning summary, then a single chapter of aviation unit and intermediate troubleshooting procedures.

• Warning Summary — hearing protection, solvent fumes, FRIES bar lift, external carry, rope-to-rotor hazards, radar altimeter limits in foliage, FRIES visibility, first aid reference to FM 4-25.11
• Chapter 2 — Aviation Unit and Intermediate Maintenance Troubleshooting Procedures for Army model helicopters UH-60A, UH-60L, EH-60A, HH-60A, and HH-60L
• Position Transmitter/Limit Switch Assembly (AVIM) — WP 0072 00
• Parking Brake System — WP 0073 00
• Tail Wheel Lock System — WP 0074 00
• Engine and Engine Interface — WP 0075 00
• No. 1 Engine Instruments and Warning Lights System — WP 0076 00
• No. 1 Engine Instruments and Warning Lights System UH-60A UH-60L IVHMS — WP 0076 01
• No. 2 Engine Instruments and Warning Lights System — WP 0077 00
• No. 2 Engine Instruments and Warning Lights System UH-60A UH-60L IVHMS — WP 0077 01
• Engine Overspeed Protection System — WP 0078 00
• Engine Speed Trim System — WP 0079 00
• Engine Chip Detector System — WP 0080 00
• Engine Anti-ice System — WP 0081 00
• Engine Start and Ignition System — WP 0082 00
• Engine Controls Quadrant (AVIM) — WP 0083 00
• BIM Indicators — WP 0084 00
• Main Rotor Blades (AVIM) — WP 0085 00
• Medium and High Frequency Vibrations — WP 0086 00
• Gust Lock System — WP 0087 00
• Transmission Chip Detector, Instruments, and Oil Warning Systems — WP 0088 00
• Transmission Chip Detector, Instruments, and Oil Warning Systems UH-60A UH-60L IVHMS — WP 0088 01
• Hydraulic Systems — WP 0089 00
• Pitot-Static System — WP 0090 00
• Pitot Heater — WP 0091 00
• Instrument Display System — WP 0092 00
• Instrument Display System UH-60A UH-60L IVHMS — WP 0092 01
• Caution/Advisory Warning System — WP 0093 00
• Caution/Advisory Warning System UH-60A UH-60L IVHMS — WP 0093 01
• Digital Clock — WP 0094 00
• Central Display Unit (70450-01043-122) (AVIM) — WP 0095 00
• Central Display Unit (1006448-10 or 1006448-30) (AVIM) — WP 0095 01
• Central Display Unit (70450-01043-125, 70450-21943-118, or 70450-01916-105) (AVIM) — WP 0096 00
• Pilots Display Unit (AVIM) — WP 0097 00
• Signal Data Converter (SDC) (70450-01043-112 or 70450-01043-126) (AVIM) — WP 0098 00
• Signal Data Converter (SDC) (70450-21943-110 or 70450-01916-103) (AVIM) — WP 0099 00
• Caution/Advisory Panel (AVIM) — WP 0100 00
• Caution/Advisory Panel (LED) (AVIM) — WP 0101 00
• Chip Detector Resistor Unit (AVIM) — WP 0102 00
• Miscellaneous Switch Panel (AVIM) — WP 0103 00
• MFD/Caution/Advisory Warning System HH-60A HH-60L — WP 0104 00

Taken together, those work packages give the technician a fault-isolation path for landing gear brakes and tail-wheel lock, engine interface and indicating systems, rotor and drive indicators, hydraulics, pitot-static and heaters, and the cockpit display and caution architecture used on these five airframes. Location drawings and schematic sheets sit inside each package so checks can be made at the named connectors, circuit breakers, and valves.

Landing Gear and Airframe Checks

Parking brake troubleshooting in WP 0073 00 starts with circuit breakers on the upper console and copilot panel (CAUT/ADVSY PNL, LIGHTS ADVSY, LIGHTS CAUT/ADVSY), electrical power, and a firm-pedal checkout. If pedals bottom with no resistance, the flow checks lines for leaks and master-cylinder fluid level. When the parking brake handle is pulled with the tailwheel unlocked, the PARKING BRAKE ON capsule must illuminate, the handle must stay up, and the helicopter must not roll when the tail cone is pushed. Release is confirmed by a tap on the left brake pedal. Separate trees cover a dark PARKING BRAKE ON capsule (linkage, indicator lamp test, EMEP pin-filtered adapters P118 / P1019R / P1020R, 28 VDC at P118-H or P1019R-33 / P1020R-33, LIGHTS ADVSY breaker, continuity through switch S42) and brakes that do not hold (leaks, wear-indicator pin flush with the wheel-brake housing, pads versus parking-brake valve).

Tail wheel lock WP 0074 00 checks lockpin alignment, the miscellaneous switch panel TAIL WHEEL switch, and four mismatch cases: pin will not disengage while the switch reads LOCK, pin disengages but the switch still reads LOCK, pin will not engage while the switch reads UNLK, and pin engages but the switch still reads UNLK. Voltage is measured at P507-A/B/C and P135, continuity at J135 and J507, and actuator position (retracted or extended) is confirmed before linkage or lockpin replacement is called.

Stabilator position transmitter and limit-switch work at AVIM (WP 0072 00) is a bench checkout. The assembly is cleaned, inspected, and connected to a locally made test unit at P604/J604 and P605/J605 with stabilator indicators on P116 and P471R and an angle position indicator on the S1/S2/S3 and REF tipjacks. Pivot-arm travel must drive the indicators smoothly from -8° up to +40° down. Locked +10° down must read 350.5° to 352.5° on the API; transmitter nuts torque to 19–21 inch-pounds after adjustment. Up and down limit lamps (#1/#2 UP and #1/#2 DN) are set at the -8° and +40° slots, with API windows of 7°–9° and 300.5°–323.5° used to decide whether the baseplate or retainer must be replaced.

Engine Interface, Instruments, and Related Systems

Engine and engine interface WP 0075 00 isolates airframe causes first. A self-test BITE table on the torque meter maps 15% through 125% indications to DEC, Np demand, load share, TGT, alternator power, Ng, Np, torque, overspeed, hot-start prevention, 400 Hz power, collective channel, and Nr, sending the technician either into this volume (instrument display WP 0092 00, overspeed WP 0076 00, power WP 0106 00) or to TM 1-2840-248-23. A dedicated tree covers engine Ng low at ground idle. Companion packages then treat No. 1 and No. 2 engine instruments and warning lights, including the IVHMS variants; overspeed protection; speed trim; chip detector; anti-ice; start and ignition; and the engine controls quadrant at AVIM.

Rotor and drive coverage includes BIM indicators, AVIM main-rotor blade work, medium and high frequency vibration isolation, the gust lock, and transmission chip detector, instruments, and oil warning systems with a separate IVHMS package. Hydraulic systems occupy WP 0089 00. Pitot-static and pitot heater packages precede the instrument display system and its IVHMS counterpart.

Displays, Caution Panels, and AVIM Bench Units

Caution and advisory warning is written both in standard form and for UH-60A/UH-60L IVHMS. Digital clock checkout sits in WP 0094 00. Intermediate-level bench procedures then cover three central display unit part-number families (70450-01043-122; 1006448-10 or 1006448-30; and 70450-01043-125, 70450-21943-118, or 70450-01916-105), the pilots display unit, two signal data converter families, standard and LED caution/advisory panels, the chip detector resistor unit, and the miscellaneous switch panel. HH-60A and HH-60L MFD caution/advisory warning is isolated in WP 0104 00, matching the T6 legend-test step used when those aircraft are powered up for parking-brake checks.

Typical test equipment called in the initial-setup blocks includes multimeter AN/PSM-45A, angle position indicator 8810-F1110, stabilator indicators ID-2279/A, electrical repairer toolkit SC5180-99-B06, aircraft mechanic toolkit SC5180-99-B01, and a 0–30 in-lb torque wrench. Bench power for the position transmitter is specified as 27–28 VDC and 115 VAC, 400 Hz, single phase.

How the Procedures Are Built

Each work package follows the same technician-facing pattern: initial setup (test equipment, tools, personnel MOS where listed, references, equipment condition such as external power WP 1737 00 or APU per TM 1-1520-237-10), operational checkout with numbered steps, condition/indication statements, and corrective actions that branch to a named malfunction tree. Circuit-breaker pop-out is treated as a short and sent to WP 0108 00. Connector identifiers, pin letters, and schematic sheet numbers are printed in the trees so a meter lead can be placed without guessing. Location diagrams show cockpit, cabin station, tail cone, and relay-panel plugs; schematic sheets separate electrical, mechanical, and hydraulic lines.

This UH-60A UH-60L EH-60A HH-60A HH-60L Aviation Unit Intermediate Maintenance Troubleshooting Manual TM 1-1520-237-23-2 Volume 2 also carries metric conversion tables and DA Form 2028 / electronic 2028 instructions at the back of the file. Distribution Statement D and the Arms Export Control Act warning printed on the title page remain part of the document as published on 30 May 2014.

Use This Manual on the Aircraft

With this volume a unit or intermediate technician can run operational checkouts and isolate faults on the parking brake and tail-wheel lock, set and verify the stabilator position transmitter and limit switches, sort engine-interface BITE readings from airframe indicating faults, work engine instrument and warning-light paths including IVHMS, and bench-test display units, signal data converters, caution panels, and the miscellaneous switch panel. Correct torque (19–21 inch-pounds on transmitter and limit-switch hardware), API angle windows, 28 VDC pin checks, and the EDECU DAS-plug warning matter because the procedures are written around those values. Instant PDF delivery after payment — no shipping wait — so the file can be opened on any device and printed for the hangar or bench.