# AD 91-16-07: Altimeter Repeater Units

- Type: Airworthiness directive
- Status: Current
- Products: BAE Systems ATP
- Effective: September 11, 1991
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-7097
- Docket: 91-NM-79-AD
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C779182C7DFCC3DB86256A1D00682DD4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/91-16-07

## The airworthiness directive

91-16-07 BRITISH AEROSPACE: Amendment 39-7097. Docket No. 91-NM-79-AD. Applicability: Model ATP series airplanes, equipped with Smiths Industries Altimeter Repeater Units, Part Number 1205AM1, certificated in any category.

Compliance: Required within 120 days after the effective date of this AD, unless previously accomplished.

To ensure the pilot receives accurate altitude data, accomplish the following:

A. Install a hardened knobshaft, Part Number AM10588, in place of Part Number AM10454, and remount the microswitch (Smiths Industries Modification No. 02), in accordance with British Aerospace Service Bulletin ATP-34-40, dated October 20, 1990.

NOTE: The British Aerospace service bulletin references Smiths Industries Service Bulletin 1205AM-34-756 for additional instructions.

B. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

D. The modification requirement shall be done in accordance with British Aerospace Service Bulletin ATP-34-40, dated October 20, 1990. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041. Copies may be inspected at the FAA, Transport Airplane Directorate, Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

This amendment (39-7097, AD 91-16-07) becomes effective on September 11, 1991.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A27NM](https://openairdocs.org/tcds/A27NM): BAE Systems (Operations) Limited; names 1 of 1 models: ATP

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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