# AD 91-25-01: Horizontal Stabilizer Trim

- Type: Airworthiness directive
- Status: Current
- Products: Gulfstream Aerospace LP 1125 Westwind Astra
- Effective: December 10, 1991
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-8102
- Docket: 91-NM-219-AD
- Registered aircraft: 36 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4754F5EC644DDE4486256A2A0061401E.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/91-25-01

## The airworthiness directive

91-25-01 ISRAEL AIRCRAFT INDUSTRIES (IAI), LTD.: Amendment 39-8102. Docket No. 91- NM-219-AD. Applicability: All Model 1125 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent uncontrolled pitch trim movement, accomplish the following:

  (a) Within 3 days after the effective date of this AD, revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following. This may be done by inserting a copy of this AD in the AFM.

"BEFORE TAXIING Horizontal stabilizer trim - CHECK OVERRD & EMERG; EMERG ARM pushbutton - DISENGAGE, CHECK NORMAL (buzzer)

NOTE

When checking override system, observe trim indicator; electrical limit switches are inoperative.

CAUTION

Do not use emergency trim in place of normal or override trim systems. Use of emergency trim is limited to elevator control failure (Section II, page II-28) and horizontal stabilizertrim failure (Section III, page III-9)."

NOTE: Inserting Astra (Model 1125) AFM Temporary Revision No. 3, dated June 9, 1991, in the Limitations section of the AFM, or inserting an AFM revision containing this information, is considered an acceptable alternative method of compliance with this paragraph.

  (b) Within 3 days after the effective date of this AD, revise the Normal Procedures Section of the FAA-approved AFM to include the following. This may be done by inserting a copy of this AD in the AFM.

"BEFORE TAXIING Horizontal stabilizer trim - CHECK OVERRD & EMERG; EMERG ARM pushbutton - DISENGAGE, CHECK NORMAL (buzzer)

NOTE

When checking override system, observe trim indicator; electrical limit switches are inoperative.

CAUTION

Do not use emergency trim in place of normal or override trim systems. Use of emergency trim is limited to elevator control failure (Section II, page II-28) and horizontal stabilizer trim failure (Section III, page III-9)."

NOTE: Inserting Astra (Model 1125) AFM Temporary Revision No. 3, dated June 9, 1991, in the Procedures Section of the AFM, or inserting an AFM revision containing this information, is considered an acceptable alternative method of compliance with this paragraph.

  (c) 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 Operations Inspector, who may concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

  (d) 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.

  (e) This amendment (39-8102, AD 91-25-01) becomes effective on December 10, 1991.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A16NM](https://openairdocs.org/tcds/A16NM): Gulfstream Aerospace LP; names 1 of 4 models: 1125 Westwind Astra

## 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: 36 (36 by airframe model, 0 by engine model)
- Makers: Israel Aircraft Industries 36

Models with the most aircraft:

- [Israel Aircraft Industries 1125 WESTWIND ASTRA](https://openairdocs.org/model/israel-aircraft-industries-1125-westwind-astra): 36 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/91-25-01/models.md
Every aircraft: https://openairdocs.org/ad/91-25-01/aircraft.md

Its text cites no advisory circulars or STCs.

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