# AD 77-24-01: Stabilizers and Fins

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-31, PA-31-325 and PA-31-350
- Effective: April 17, 1978
- Published: April 13, 1978
- Issued: April 3, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-3182
- Registered aircraft: 562 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1A3C4C2803ADDA2A86256E1200559FD6.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/77-24-01

## The airworthiness directive

77-24-01 PIPER: Amendment 39-3083 as amended by Amendment 39-3182. Applies to the following models: PA-31 and PA-31-325, Serial Nos. 31-465, 31-7712057 thru 31-7712078, 31-7712081 and 31-7712083; PA-31-350 Serial Nos. 31-7752099, 31-7752101, 31-7752103, 31- 7752105 thru 31-7752114, 31-7752117 thru 31-7752131 and 31-7752134 thru 31-7752138, certificated in all categories.

To prevent possible hazards in flight associated with missing horizontal stabilizer and fin skin to stiffener rivet attachments, accomplish the following within the next fifty hours in service from the effective date of this AD unless previously accomplished:

  (a) Inspect and, if required, repair the horizontal stabilizer and fin skin to stiffener rivet attachments in accordance with the "Instructions" section of Piper Service Bulletin No. 575 or equivalent procedures which must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

  (b) Upon submission of substantiatingdata through an FAA Maintenance Inspector, the compliance time specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.

The affected airplanes may be flown in accordance with FAR 21.197 to a location where the AD compliance procedures can be accomplished.

Amendment 39-3083 was effective November 24, 1977.

This amendment 39-3182 is effective April 17, 1978.

## 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 3 of 4 models: PA-31, PA-31-325, 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: 562 (562 by airframe model, 0 by engine model)
- Makers: Piper 562

Models with the most aircraft:

- [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350): 399 aircraft (airframe model)
- [Piper PA-31-325](https://openairdocs.org/model/piper-pa-31-325): 137 aircraft (airframe model)
- [Piper PA-31](https://openairdocs.org/model/piper-pa-31): 26 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/77-24-01/models.md
Every aircraft: https://openairdocs.org/ad/77-24-01/aircraft.md

Its text cites no advisory circulars or STCs.

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