# AD 81-25-04 R1: Electrical Wiring Inspection

- Type: Airworthiness directive
- Status: Current
- Products: Mitsubishi Heavy Industries MU-2B-25, MU-2B-26, MU-2B-26A, MU-2B-35, MU-2B-36A, MU-2B-40 and MU-2B-60
- Effective: January 21, 1982
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-4300
- Registered aircraft: 157 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2E1081939448944986256A4D00458FCC.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/81-25-04-R1

## The airworthiness directive

81-25-04 R1 MITSUBISHI AIRCRAFT INTERNATIONAL, INC. (MAI): Amendment 39- 4274 as amended by amendment 39-4300. Applies to MAI Models MU-2B-25/-26/-26A/-40, serial numbers 313SA, 321SA, 348SA through 453SA, Models MU-2B-35/-36A/-60, serial numbers 652SA, 661SA, 697SA through 799SA, 1501SA through 1538SA, and 1540SA.

Compliance is required as indicated unless previously accomplished.

Within the next 25 hours' time in service from the effective date of this AD: 1. Visually inspect the engine's electrical wiring to determine if nonshielded and noncolor coded wiring is white or brown (tan). Inspection may be made at connectors P4001 and P4020. Remove spiral wrap as required for inspection.

2. If wires are brown (tan) inspect in accordance with Figure 1 (one) to determine if wires are "tight weave" or "loose weave." a. If brown (tan) wires are "loose weave," inspect in accordance with paragraph 4. b. If brown (tan) wires are "tight weave," no further inspection is necessary and the airplane may be returned to service.

3. If wires are white, open the harness as necessary and inspect wires for identification: a. If white wires are marked MS 25471-XX (XX indicates wire gauge), inspect in accordance with paragraph 4. b. If white wires are marked M 22759/5-XX, no further inspection is necessary and the airplane may be returned to service.

4. After each 25 hours' time in service, remove wiring harness which incorporates wires affected by paragraph 2a or 3a from the engines and visually inspect all brown (tan) "loose weave" or white insulated MS 25471-XX wires for tight loop, kinks, or bulged deformation. If these conditions are found, replace the wiring harness using one of the procedures in paragraph 5 before further flight. Inspections may be discontinued when wires are replaced using one of the procedures in paragraph 5.

5. Before 300 hours' time in service, after the effective date of this AD, replace all brown (tan) "loose weave" orwhite insulated MS 25471-XX wires with M 22759/8-XX wire using one of the procedures specified in Part 3 of MAI S/B SB036/71-003, Revision A, or alternate means approved by the Chief, Aircraft Certification Division, Southwest Region, Federal Aviation Administration.

A special flight permit may be issued in accordance with FAR 21.197 to allow flight of the airplane to a location where this AD can be accomplished.

Amendment 39-4274 became effective December 10, 1981. This amendment 39-4300 becomes effective January 21, 1982.

AD 81-25-04

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A10SW](https://openairdocs.org/tcds/A10SW): Mitsubishi Heavy Industries Ltd.; names 4 of 6 models: MU-2B-26A, MU-2B-36A, MU-2B-60, MU-2B-40
- [TCDS A2PC](https://openairdocs.org/tcds/A2PC): Mitsubishi Heavy Industries Ltd. 203; names 1 of 7 models: MU-2B-35

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 157 (157 by airframe model, 0 by engine model)
- Makers: Mitsubishi 157

Models with the most aircraft:

- [Mitsubishi MU-2B-60](https://openairdocs.org/model/mitsubishi-mu-2b-60): 50 aircraft (airframe model)
- [Mitsubishi MU-2B-40](https://openairdocs.org/model/mitsubishi-mu-2b-40): 35 aircraft (airframe model)
- [Mitsubishi MU-2B-25](https://openairdocs.org/model/mitsubishi-mu-2b-25): 23 aircraft (airframe model)
- [Mitsubishi MU-2B-26A](https://openairdocs.org/model/mitsubishi-mu-2b-26a): 19 aircraft (airframe model)
- [Mitsubishi MU-2B-26](https://openairdocs.org/model/mitsubishi-mu-2b-26): 16 aircraft (airframe model)
- [Mitsubishi MU-2B-36A](https://openairdocs.org/model/mitsubishi-mu-2b-36a): 10 aircraft (airframe model)
- [Mitsubishi MU-2B-35](https://openairdocs.org/model/mitsubishi-mu-2b-35): 4 aircraft (airframe model)

All 7 models: https://openairdocs.org/ad/81-25-04-R1/models.md
Every aircraft: https://openairdocs.org/ad/81-25-04-R1/aircraft.md

Its text cites no advisory circulars or STCs.

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