# AD 85-21-01: Forward Engine Mount

- Type: Airworthiness directive
- Status: Current
- Products: Boeing 737-300 Series
- Effective: October 21, 1985
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-5148
- Registered aircraft: 8 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3F1F3F7E295036D6862568AA005DD682.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/85-21-01

## The airworthiness directive

85-21-01 BOEING: Amendment 39-5148. Applies to all Model 737-300 series airplanes delivered prior to line position 1147, certificated in any category. Line position 1147 was delivered September 13, 1985. To detect loose cone bolts and interference between the engine and engine support strut at the forward engine mount, accomplish the following within 30 days after the effective date of this AD, unless already accomplished:

A. Visually inspect for clearances between the engine and engine support strut in the vicinity of the forward engine mount as specified in Boeing Telegraphic Service Letter M- 7272-2396, dated September 12, 1985.

B. If the required clearance cannot be confirmed at any location specified in Boeing Telegraphic Service Letter M-7272-2396, dated September 12, 1985, lower the engine in accordance with Boeing Maintenance Manual Section 71-00-02, revised June 25, 1985, sufficiently to accomplish the following:

1. Disassemble as required to inspect theforward cone bolts and forward mount cone bolt receptacles for pitting, galling, or wear and clearances in accordance with Boeing Maintenance Manual Section 71-21-00, revised October 25, 1984.

2. Penetrant-inspect the cone bolt threads as specified in Boeing Telegraphic Service Letter M-7272-2396, dated September 12, 1985.

3. Repair or replace any damaged cone bolts or cone bolt receptacles.

C. Eliminate interference detected in paragraph A., above, in accordance with procedures specified in Boeing Telegraphic Service Letter M-7272-2396, dated September 12, 1985.

D. Following accomplishment of the above, reinstall the engine in accordance with instructions provided in Maintenance Manual Section 71-00-02, revised June 25, 1985, except that the cone bolts must be tightened to 1200-1400 inch-pounds of torque.

E. 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.

F. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

All persons affected by this AD who have not already received copies of the service information cited herein may obtain copies upon request from the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective October 21, 1985.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A16WE](https://openairdocs.org/tcds/A16WE): The Boeing Company; names 1 of 17 models: 737-300 Series

## 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: 8 (8 by airframe model, 0 by engine model)
- Makers: Boeing 8

Models with the most aircraft:

- [Boeing 737-300](https://openairdocs.org/model/boeing-737-300): 4 aircraft (airframe model)
- [Boeing 737-301](https://openairdocs.org/model/boeing-737-301): 1 aircraft (airframe model)
- [Boeing 737-306](https://openairdocs.org/model/boeing-737-306): 1 aircraft (airframe model)
- [Boeing 737-319](https://openairdocs.org/model/boeing-737-319): 1 aircraft (airframe model)
- [Boeing 737-330](https://openairdocs.org/model/boeing-737-330): 1 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/85-21-01/models.md
Every aircraft: https://openairdocs.org/ad/85-21-01/aircraft.md

Its text cites no advisory circulars or STCs.

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