# AD 83-21-03: Ground Spoiler System

- Type: Airworthiness directive
- Status: Current
- Products: Viking Air DHC-7-1, DHC-7-100, DHC-7-101, DHC-7-102 and DHC-7-103
- Effective: November 2, 1983
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-4753
- Registered aircraft: 7 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D99BBEB089AAC47C862569EC005FBBCE.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/83-21-03

## The airworthiness directive

83-21-03 DEHAVILLAND AIRCRAFT OF CANADA, LTD.: Amendment 39-4753. Applies to DeHavilland model DHC-7 airplanes, certificated in all categories, which are equipped with ground spoiler valves installed in accordance with DeHavilland modification No. 7/1732. To detect failures of the pilot valve of the ground spoiler valve No. 2, accomplish the following, unless previously accomplished:

A. Within 25 flight hours from the effective date of this AD, perform an operational check of the ground spoiler system, and take appropriate corrective action, if necessary, in accordance with the Accomplishment Instructions of DeHavilland Aircraft of Canada, Ltd., Alert Service Bulletin A7-27-56, dated June 28, 1983.

B. Repeat the functional checks of paragraph A. at intervals not to exceed 800 flight hours.

C. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest MountainRegion.

D. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD.

This amendment becomes effective November 2, 1983.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A20EA](https://openairdocs.org/tcds/A20EA): De Havilland Aircraft of Canada Limited; names 5 of 5 models: DHC-7-101, DHC-7-103, DHC-7-102, DHC-7-100, DHC-7-1

## 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: 7 (7 by airframe model, 0 by engine model)
- Makers: Dehavilland 7

Models with the most aircraft:

- [Dehavilland DHC-7-102](https://openairdocs.org/model/dehavilland-dhc-7-102): 5 aircraft (airframe model)
- [Dehavilland DHC-7-103](https://openairdocs.org/model/dehavilland-dhc-7-103): 2 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/83-21-03/models.md
Every aircraft: https://openairdocs.org/ad/83-21-03/aircraft.md

Its text cites no advisory circulars or STCs.

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