# AD 74-12-10: Auxiliary Power Unit

- Type: Airworthiness directive
- Status: Current
- Products: Mitsubishi Heavy Industries YS-11, YS-11A-200, YS-11A-300, YS-11A-500 and YS-11A-600
- Effective: June 12, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-1866
- Registered aircraft: 1 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/6F4144708EFF08D3862569BA0075EC96.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-12-10

## The airworthiness directive

74-12-10 NIHON AEROPLANE MANUFACTURING COMPANY LIMITED: Amendment 39-1866. Applies to NAMC Model YS-11/11A series airplanes (S/N's 2050 through 2053, 2056, 2057, 2061, 2062, 2072, 2073, 2075, 2077, 2079, 2084, 2086 through 2089, 2091, 2100, 2118 through 2123, 2126, 2128, 2129, 2132, 2140, 2148, 2159, 2169, 2172, 2173, and 2179 through 2181) equipped with AiResearch APU's.

Compliance required within the next 25 hours' time in service after the effective date of this AD unless already accomplished.

To prevent possible malfunction in the auxiliary power unit (APU) wiring harness that could result in a fire, inspect and modify the installation of the APU electrical wiring harnesses in accordance with the Japan Civil Aviation Bureau approved NAMC YS-11 Service Bulletin No. A49-13, dated February 25, 1974 or an equivalent approved by the Chief, Engineering and Manufacturing District Office, FAA, Pacific-Asia Region.

This amendment becomes effective June 12, 1974.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A1PC](https://openairdocs.org/tcds/A1PC): Mitsubishi Heavy Industries Ltd.; names 5 of 5 models: YS-11, YS-11A-300, YS-11A-500, YS-11A-600, YS-11A-200

## 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: 1 (1 by airframe model, 0 by engine model)
- Makers: Nihon 1

Models with the most aircraft:

- [Nihon YS-11A-500](https://openairdocs.org/model/nihon-ys-11a-500): 1 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/74-12-10/models.md
Every aircraft: https://openairdocs.org/ad/74-12-10/aircraft.md

Its text cites no advisory circulars or STCs.

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