# AD 57-21-01: Rudder Trim Tab Pin

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-23
- Published: January 23, 1958
- Issued: January 23, 1958
- Superseded by: Nothing supersedes this AD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/397E2BF0ADB873888625698B00764ED0.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/57-21-01

## The airworthiness directive

57-21-01 PIPER: Applies to All Model PA-23 Aircraft.

Compliance required at next regular inspection period but not to exceed 100 hours.

Inspect the attachment of the rudder trim tab control rod to the rudder trim tab. If a flat head pin has been installed it must be replaced by an AN 23-10 clevis bolt and AN 960-10L washer, secured with an AN 320-3 nut and AN 380-2-2 cotter pin.

(Piper Service Bulletin No. 159 covers this 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/57-21-01/models.md
Every aircraft: https://openairdocs.org/ad/57-21-01/aircraft.md

Its text cites no advisory circulars or STCs.

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