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55-21-02: Front Wing Spar Attachment Fitting

FAA order 55-21-02 is an airworthiness directive published December 4, 1956. The FAA's subject line: Front Wing Spar Attachment Fitting. It names Piper PA-23 Apache and Aztec: about 1,315 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: airframe structure.

What it applies to as the FAA lists it

Kind of product
Aircraft
Makes
Piper Aircraft Inc.
Models
PA-23
On this site
Piper PA-23 Apache and Aztec 1,315 registered

Dates and paperwork

Published
December 4, 1956
Docket
Unknown
Status
Current
The FAA's document
Read the order on the FAA's site

The order itself the regulatory text, as published

Show the full text (1,147 characters)
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.)

Related safety bulletins advice on the same designs, not orders

2018-11-21SW-18-31 · NAVIGATION, ATTITUDE, AND DIRECTION DATA SYSTEM
2017-02-21CE-17-08 · Main Landing Gear Drag Link Bolt
2012-09-17CE-12-44 · Exhaust systems
2008-01-09CE-08-11 · Landing Gear
2005-07-07CE-05-67 ·

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 30, 2026. Connections as data: /graph/directive/55-21-02.json · aircraft systems.