# AD 79-26-01: Stabilator Skins and Frame

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-23-250 and PA-23-250 (Navy UO-1)
- Effective: December 24, 1979
- Published: December 17, 1979
- Issued: December 7, 1979
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-3639
- Registered aircraft: 899 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0DD2F7F173735C328625699E007694A1.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/79-26-01

## The airworthiness directive

79-26-01 PIPER: Amendment 39-3639. Applies to Piper PA-23-250 Model airplanes, Serial Nos. 27-7654001 thru 27-7954044 certificated in all categories, which incorporate the following stabilators.

Serial Nos.: 0336-L thru 0340-L 0401-L thru 0607-L 0337-R thru 0341-R 0402-R thru 0609-R

To prevent possible loosening and relative motion between the stabilator bottom skins and the stabilator frame - structure, accomplish the following:

a. Within the next 50 hours in service after the effective date of this AD, unless already accomplished within the past 50 hours and at intervals not to exceed 100 hours in service thereafter, inspect and repair or alter the left and right stabilator in accordance with the "INSTRUCTIONS" section on page 3 of 3 in Piper Service Bulletin No. 606 dated July 12, 1979, or approved equivalent.

b. When the stabilator assemblies are altered in accordance with paragraph B.4. of the "INSTRUCTIONS" section or equivalent, compliance with this AD is no longer required.

c. Equivalent inspections, repairs or alterations must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

d. Upon submission of substantiating data through an FAA Maintenance Inspector, the compliance time specified in this AD may be adjusted by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

This amendment is effective December 24, 1979.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A10](https://openairdocs.org/tcds/1A10): Piper Aircraft Inc.; names 1 of 6 models: PA-23-250 (Navy UO-1)

## 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: 899 (899 by airframe model, 0 by engine model)
- Makers: Piper 899

Models with the most aircraft:

- [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250): 894 aircraft (airframe model)
- [Piper PA-23-250 (6PCLM)](https://openairdocs.org/model/piper-pa-23-250-6pclm): 5 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/79-26-01/models.md
Every aircraft: https://openairdocs.org/ad/79-26-01/aircraft.md

Its text cites no advisory circulars or STCs.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.