# AD 79-14-03: Hydraulic System

- Type: Airworthiness directive
- Status: Current
- Products: Lockheed Martin L-1011-385-1, L-1011-385-1-14 and L-1011-385-1-15
- Effective: July 16, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-3511
- Registered aircraft: 3 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2A78237CAAAE57498625697500492208.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/79-14-03

## The airworthiness directive

79-14-03 LOCKHEED CALIFORNIA: Amendment 39-3511. Applies to Lockheed L-1011-385-1 series airplanes certificated in all categories.

Compliance required within the next 350 hours time in service, unless already accomplished.

To prevent uncontrolled pressure buildup in the hydraulic system return lines and to maintain full flight control capability, accomplish the following:

  (a) Remove the hydraulic system return filter module inlet shutoff valve assemblies from the hydraulic system return filter modules per Lockheed Service Bulletin 093-29-069, dated June 27, 1979.

  (b) Equivalent modifications may be approved by the Chief, Aircraft Engineering Division, FAA Western Region.

  (c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a base to perform the required modifications.

This amendment becomes effective July 16, 1978.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A23WE](https://openairdocs.org/tcds/A23WE): Lockheed Martin Corporation; names 3 of 4 models: L-1011-385-1-14, L-1011-385-1, L-1011-385-1-15

## 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: 3 (3 by airframe model, 0 by engine model)
- Makers: Lockheed 3

Models with the most aircraft:

- [Lockheed L-1011-385-1](https://openairdocs.org/model/lockheed-l-1011-385-1): 2 aircraft (airframe model)
- [Lockheed L-1011-385-1-15](https://openairdocs.org/model/lockheed-l-1011-385-1-15): 1 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/79-14-03/models.md
Every aircraft: https://openairdocs.org/ad/79-14-03/aircraft.md

Its text cites no advisory circulars or STCs.

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