# AD 73-11-06: Engine Overheat

- Type: Airworthiness directive
- Status: Current
- Products: Maule Aerospace Technology M-4-180C, M-4-220C and M-4-220S
- Effective: May 29, 1973
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1646
- Registered aircraft: 87 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/530531E86F02A73486256A38006512C8.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-11-06

## The airworthiness directive

73-11-06 MAULE: Amdt. 39-1646. Applies to Models M-4-180 and M-4-220 certificated in all categories as indicated below.

Compliance required within the next 50 hours' time in service after the effective date of this airworthiness directive.

To prevent possible engine overheat during climb and to obtain a correct cylinder head temperature reading accomplish the following or an equivalent approved by Chief, Engineering and Manufacturing Branch, Southern Region:

1. For Model M-4-220C serial numbers 2135C through 2175C and 2177C: Install Maule slug P/N 6002B-3 in the No. 4 cylinder head thermocouple hole in accordance with Maule Service Letter No. 25. The slug is to be installed prior to relocation of cylinder head sender unit.

2. For Model M-4-180C serial numbers 3001C through 3006C; Model M-4-220S, Serial Number 2001S; Model M-4-220C; Serial Numbers 2001C through 2126C, 2129C through 2175C, and 2177C: Relocate the cylinder head temperature sender to the No. 4 cylinder head in accordance with Maule Service Letter No. 24.

3. For Model M-4-180C, Serial Numbers 3002C through 3006C, and Model M-4-220C Serial Numbers 2053C through 2126C, 2129C through 2175C and 2177C: Install engine top baffle, Maule P/N 5031X-3, in accordance with Maule Service Letter No. 26.

This amendment becomes effective May 29, 1973.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 3A23](https://openairdocs.org/tcds/3A23): Maule Aerospace Technology Inc.; names 3 of 50 models: M-4-180C, M-4-220C, M-4-220S

## 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: 87 (87 by airframe model, 0 by engine model)
- Makers: Maule 87

Models with the most aircraft:

- [Maule M-4-220C](https://openairdocs.org/model/maule-m-4-220c): 83 aircraft (airframe model)
- [Maule M-4-180C](https://openairdocs.org/model/maule-m-4-180c): 4 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/73-11-06/models.md
Every aircraft: https://openairdocs.org/ad/73-11-06/aircraft.md

Its text cites no advisory circulars or STCs.

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