# AD 55-21-02: Front Wing Spar Attachment Fitting

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-23
- Published: December 4, 1956
- Issued: December 4, 1956
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 155 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2960192A596316E38625698B00764A15.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/55-21-02

## The airworthiness directive

55-21-02 PIPER: Applies to All Model PA-23 Aircraft Through Serial Number 23-321, Except Serial Numbers 23-310, -311, -315, and -319.

Compliance required as indicated.

The wing front spar attachment fitting P/N 17079 at the centerline of the fuselage must be inspected and reinforced as indicated below. This is a welded steel fitting bolted to the front face of the front spar web and is accessible through the wing bottom access panel.

I. Compliance required prior to next flight and at every 15 hours thereafter. Visually inspect the wing front spar attachment fitting and if any damage is found such as bent flanges or any other visible distortion contact the Piper Corp. for further instruction prior to returning airplane to flight status.

II. Compliance required prior to November 1, 1955. If inspection of item I discloses no defects install reinforcement fitting assembly in accordance with Piper reinforcement Kit 754112 or equivalent. The inspections required in item I are not required after incorporating the fitting reinforcement.

(Piper Service Bulletin No. 142 dated October 4, 1955, covers this same subject.)

## 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

## 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: 155 (155 by airframe model, 0 by engine model)
- Makers: Piper 155

Models with the most aircraft:

- [Piper PA-23](https://openairdocs.org/model/piper-pa-23): 155 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/55-21-02/models.md
Every aircraft: https://openairdocs.org/ad/55-21-02/aircraft.md

Its text cites no advisory circulars or STCs.

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