# AD 74-17-03: Cabin Heater Inspection

- Type: Airworthiness directive
- Status: Current
- Products: Viking Air DHC-2 Mk.I
- Effective: August 12, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1914
- Registered aircraft: 116 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E5054B5151D822EB86256A380048D2CB.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-17-03

## The airworthiness directive

74-17-03 DEHAVILLAND: Amendment 39-1914. Applies to Model DHC-2 (Mk I) Beaver Airplane. Compliance required within the next 110 hours in service after the last inspection pursuant to this directive and thereafter at intervals not to exceed 110 hours in service from a preceding inspection.

To prevent carbon monoxide from entering the airplane cabin, accomplish the following:

  (a) For airplanes using the intensifier tube cabin heater system, remove the tube and perform a visual inspection on both the intensifier tube and the exhaust pipe for any holes, cracks, flaking or weld separations.

  (b) For airplanes using heater jackets, remove the jacket and perform the same inspection as in (a) above.

Replace or repair parts found to have any holes, cracks flaking or weld separations. Make welding repairs in accordance with Advisory Circular AC 43.13-1 or an FAA approved equivalent.

Upon submission of substantiation data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, Eastern Region, may adjust the repetitive inspection intervals specified in this AD.

This Directive supersedes Airworthiness Directive 57-13-02. This amendment is effective August 12, 1974.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-806](https://openairdocs.org/tcds/A-806): De Havilland Aircraft of Canada Limited; names 1 of 3 models: DHC-2 Mk.I

## 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: 116 (116 by airframe model, 0 by engine model)
- Makers: Dehavilland 111, Dehavilland Acft Of Canada 3, Dehavilland-Shawano 2

Models with the most aircraft:

- [Dehavilland DHC-2 MK. I(L20A)](https://openairdocs.org/model/dehavilland-dhc-2-mk-i-l20a): 91 aircraft (airframe model)
- [Dehavilland DHC-2 MK.I](https://openairdocs.org/model/dehavilland-dhc-2-mk-i): 20 aircraft (airframe model)
- [Dehavilland Acft Of Canada DHC-2 MK I](https://openairdocs.org/model/dehavilland-acft-of-canada-dhc-2-mk-i): 3 aircraft (airframe model)
- [Dehavilland-Shawano DHC-2 MK.I](https://openairdocs.org/model/dehavilland-shawano-dhc-2-mk-i): 2 aircraft (airframe model)

All 4 models: https://openairdocs.org/ad/74-17-03/models.md
Every aircraft: https://openairdocs.org/ad/74-17-03/aircraft.md

## Related documents

- [AC 43.13-1B CHG 1 Ed Update](https://openairdocs.org/ac/43.13-1): Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair. Cited as AC 43.13-1 in the AD's requirements

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