# AD 86-25-03: Elevator Trim Tab - Type: Airworthiness directive - Status: Current - Products: Bombardier DHC-8-101, DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-201, DHC-8-202, DHC-8-301, DHC-8-311, DHC-8-315, DHC-7-1, DHC-7-100, DHC-7-101 and 2 more - Effective: January 12, 1987 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-5478 - Registered aircraft: 75 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B7CBC5A9F5AE2FC9862569EC00716A1A.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/86-25-03 ## The airworthiness directive 86-25-03 THE DEHAVILLAND AIRCRAFT COMPANY OF CANADA, A DIVISION OF BOEING OF CANADA, LTD.: Amendment 39-5478. Applies to all Model DHC-7 and DHC-8 series airplanes, certificated in any category. Compliance is required as indicated, unless already accomplished. To prevent the elevator trim-tab from becoming inoperable due to accumulated water freezing in the trim-tab jack-screw housing, accomplish the following, unless already accomplished. A. For Model DHC-7 airplanes, within three months after the effective date of this AD, incorporate de Havilland Modification Number 7/2489 to provide a drain hole in the elevator trim-tab jack-screw housing in accordance with the "Accomplishment Instructions" contained in de Havilland Service Bulletin No. 7-27-76, dated January 17, 1986. B. For Model DHC-8 airplanes, within three months after the effective date of this AD, incorporate de Havilland Modification Number 8/0415 to provide a drain hole in the elevator trim-tab jack-screw housing in accordance with the "Accomplishment Instructions" contained in de Havilland Service Bulletin No. 8-27-15, dated January 17, 1986. C. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety may be used when approved by the Manager, New York Aircraft Certification Office, FAA, New England Region. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain upon request to de Havilland Aircraft Company of Canada, a Division of Boeing of Canada Ltd., Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, New England Region, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York. This amendment becomes effective January 12, 1987. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A13NM](https://openairdocs.org/tcds/A13NM): De Havilland Aircraft of Canada Limited; names 9 of 16 models: DHC-8-101, DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-201, DHC-8-202, DHC-8-301, DHC-8-311… - [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: 75 (75 by airframe model, 0 by engine model) - Makers: Dehavilland 35, Bombardier 31, Boeing Of Canada/Dehav Div 6, Boeing 3 Models with the most aircraft: - [Dehavilland DHC-8-202](https://openairdocs.org/model/dehavilland-dhc-8-202): 17 aircraft (airframe model) - [Bombardier DHC-8-315](https://openairdocs.org/model/bombardier-dhc-8-315): 15 aircraft (airframe model) - [Bombardier DHC-8-202](https://openairdocs.org/model/bombardier-dhc-8-202): 14 aircraft (airframe model) - [Dehavilland DHC-7-102](https://openairdocs.org/model/dehavilland-dhc-7-102): 5 aircraft (airframe model) - [Dehavilland DHC-8-106](https://openairdocs.org/model/dehavilland-dhc-8-106): 4 aircraft (airframe model) - [Boeing DHC-8-102](https://openairdocs.org/model/boeing-dhc-8-102): 3 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-311](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-311): 3 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-106](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-106): 2 aircraft (airframe model) - [Bombardier DHC-8-201](https://openairdocs.org/model/bombardier-dhc-8-201): 2 aircraft (airframe model) - [Dehavilland DHC-7-103](https://openairdocs.org/model/dehavilland-dhc-7-103): 2 aircraft (airframe model) - [Dehavilland DHC-8-201](https://openairdocs.org/model/dehavilland-dhc-8-201): 2 aircraft (airframe model) - [Dehavilland DHC-8-103](https://openairdocs.org/model/dehavilland-dhc-8-103): 2 aircraft (airframe model) - [Dehavilland DHC-8-315](https://openairdocs.org/model/dehavilland-dhc-8-315): 2 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-102](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-102): 1 aircraft (airframe model) - [Dehavilland DHC-8-102](https://openairdocs.org/model/dehavilland-dhc-8-102): 1 aircraft (airframe model) All 15 models: https://openairdocs.org/ad/86-25-03/models.md Every aircraft: https://openairdocs.org/ad/86-25-03/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.