# AD 78-26-11: Elevator Control System

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-31-350
- Effective: January 4, 1979
- Published: December 26, 1978
- Issued: December 13, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-3380
- Registered aircraft: 399 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2071F83D0EEB76AB8625699E004AE64C.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/78-26-11

## The airworthiness directive

78-26-11 PIPER AIRCRAFT CORPORATION: Amendment 39-3380. Applies to Piper PA-31-350 Navajo Chieftain aircraft, Serial Numbers 31-5001 through 31-7852151, certificated in all categories.

Compliance required within the next 25 hours of operation after the effective date of this AD.

To insure free operation of the elevator control system, accomplish the following:

1. Install cable guide tube, Piper Part Number 71045-2, around the lightening hole in the frame at Fuselage Station 87.50, in accordance with the "Instructions" section of Piper Service Bulletin 621, dated October 13, 1978, or later edition approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region.

2. Install nylon spiral sleeving around hydraulic line in accordance with the above referenced instructions.

3. Adjust elevator control cable tension in accordance with the above referenced instructions and instructions contained in the Piper PA-31-350 Navajo Chieftain Service Manual.

Compliance with the provisions of this AD may be accomplished in an equivalent manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region.

This amendment becomes effective January 4, 1979.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A20SO](https://openairdocs.org/tcds/A20SO): Piper Aircraft Inc.; names 1 of 4 models: PA-31-350

## 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: 399 (399 by airframe model, 0 by engine model)
- Makers: Piper 399

Models with the most aircraft:

- [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350): 399 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/78-26-11/models.md
Every aircraft: https://openairdocs.org/ad/78-26-11/aircraft.md

Its text cites no advisory circulars or STCs.

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