# AD 78-26-06: Vertical Fin Attachment Plate

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-38-112
- Effective: December 26, 1978
- Published: December 26, 1978
- Issued: December 12, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-3378
- Registered aircraft: 442 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/26BF362BDFA21BB48625699E004AE582.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/78-26-06

## The airworthiness directive

78-26-06 PIPER: Amendment 39-3378. Applies to Model PA-38-112, Serial Numbers 38-78A0001 thru 38-78A0652, 38-78A0653, 38-78A0655, 38-78A0656, 38-78A0658, 38- 78A0660, 38-78A0661, 38-78A0664 thru 38-78A0672, 38-78A0674, 38-78A0676, 38-78A0677, 38-78A0680 thru 38-78A0682, 38-78A0686, 38-78A0690, 38-78A0693, 38-78A0701, 38-78A0702, 38-78A0708, 38-78A0711, 38-78A0717, 38-78A0723, 38-78A0729, 38-78A0734 and 38-78A0749 certificated in all categories.

To avoid possible hazards in flight associated with a crack in the vertical fin forward spar attachment plate accomplish the following within the next five hours in service unless previously accomplished.

a. Remove the dorsal fin fairing P/N 77607-02 and inspect the forward bend radius of the vertical fin forward spar attachment plate P/N 77553-5 for cracks using a dye penetrant inspection method.

b. If a cracked plate is found, replace with an undamaged part of the same part number before further flight, except a ferry flight to a place of repair may be authorized in accordance with FAR 21.197 with prior approval of the Chief, Engineering & Manufacturing Branch, FAA, Eastern Region.

(Piper Service Bulletin No. 628A refers to this same subject.)

This amendment is effective December 26, 1978.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A18SO](https://openairdocs.org/tcds/A18SO): Piper Aircraft Inc.; names 1 of 1 models: PA-38-112

## 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: 442 (442 by airframe model, 0 by engine model)
- Makers: Piper 442

Models with the most aircraft:

- [Piper PA-38-112](https://openairdocs.org/model/piper-pa-38-112): 442 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/78-26-06/models.md
Every aircraft: https://openairdocs.org/ad/78-26-06/aircraft.md

Its text cites no advisory circulars or STCs.

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