# AD 58-25-04: Fin Hinge Attachment

- Type: Airworthiness directive
- Status: Current
- Products: Helio H-391B and H-395 (USAF L-28A or U-10B)
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 32 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4C386A36166BAED386256A38005ED668.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/58-25-04

## The airworthiness directive

58-25-04 HELIO: Applies to Models H-391B and H-395 Aircraft Incorporating Three Fin Hinge Attachments.

Compliance required not later than next 100 hours operation or March 31, 1959, whichever occurs first.

Failure of the fin upper hinge attachment has been reported. Accordingly, the following inspection and replacement programs are required:

Inspect the fin top hinge and attachment details. Cracked parts must be replaced; uncracked parts may be reinstalled. In any case, new reinforcement gussets (P/N 391-022-001-16) must be installed.

(Helio Service Bulletin No. 18 covers this subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A8](https://openairdocs.org/tcds/1A8): Helio Alaska Inc.; names 2 of 9 models: H-395 (USAF L-28A or U-10B), H-391B

## 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: 32 (32 by airframe model, 0 by engine model)
- Makers: Helio 32

Models with the most aircraft:

- [Helio H-391B](https://openairdocs.org/model/helio-h-391b): 16 aircraft (airframe model)
- [Helio H-395](https://openairdocs.org/model/helio-h-395): 16 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/58-25-04/models.md
Every aircraft: https://openairdocs.org/ad/58-25-04/aircraft.md

Its text cites no advisory circulars or STCs.

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