# AD 66-17-02: Front and Rear Spars

- Type: Airworthiness directive
- Status: Current
- Products: Viking Air DHC-2 Mk.I, DHC-2 Mk.II and DHC-2 Mk.III
- Effective: July 22, 1966
- Published: July 12, 1966
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-259
- Registered aircraft: 140 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AE560EF36212A60086256A34006D866C.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/66-17-02

## The airworthiness directive

66-17-02 de HAVILLAND: Amdt. 39-259, Part 39, Federal Register July 12, 1966. Applies to Model DHC-2 Series (Mk 1, 2, and 3) Airplanes.

Compliance required within the next 100 hours' time in service after the effective date of this AD, unless already accomplished within the last 400 hours' time in service, and thereafter at intervals not to exceed 500 hours' time in service from the last inspection until the incorporation of Modification 2/1497, or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

To detect cracks in the wing ribs, accomplish the following:

  (a) Inspect by radiographic technique or by incorporating a special inspection panel in the wing bottom skin and inspecting visually or with dye penetrant or an equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, the wing ribs at Stations 15.50, 29.00 and 42.50 for cracks in the rib web in the upper and lower rib flanges between the front and rear spars in accordance with de Havilland Engineering Bulletin, Series "B", No. 35, Modification 2/1497, dated March 18, 1966, for Mk 1 and 2 airplanes; de Havilland Engineering Bulletin Series "T.B.", No. 3, Modification 2/1497, dated March 18, 1966, for Mk 3 airplanes; or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

  (b) Repair cracks before further flight in accordance with the applicable Engineering Bulletin specified in (a) or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

This directive effective July 22, 1966.

## 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 3 of 3 models: DHC-2 Mk.II, DHC-2 Mk.III, 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: 140 (140 by airframe model, 0 by engine model)
- Makers: Dehavilland 135, 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 III](https://openairdocs.org/model/dehavilland-dhc-2-mk-iii): 24 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 5 models: https://openairdocs.org/ad/66-17-02/models.md
Every aircraft: https://openairdocs.org/ad/66-17-02/aircraft.md

Its text cites no advisory circulars or STCs.

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