# AD 59-16-04: Damper Trunnion Bolt

- Type: Airworthiness directive
- Status: Current
- Products: Sikorsky S-58A, S-58B, S-58BT, S-58C, S-58D, S-58DT, S-58E, S-58ET, S-58F, S-58FT, S-58G, S-58H and 3 more
- Effective: April 8, 1975
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-2140
- Registered aircraft: 22 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F9152C22A1E1DA9986256A55006BDE37.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/59-16-04

## The airworthiness directive

59-16-04 SIKORSKY: Amendment 34 (24 F.R. 6581) as amended by Amendment 39-2140. Applies to all model S-58 helicopters including military types HSS-1, HSS-1F, HSS-1N, HUS-1, HUS-1A, HUS-1AN, HUS-1G, HUS-1Z, H-34A, H-34C, H-34J, CH-34A, CH-34C, HH-34F, SH-34G, SH-34H, SH-34J, UH-34D, UH-34E, UH-34G, UH-34J, VH-34C, VH-34D, except for those modified in accordance with Sikorsky Modification Kit, P/N S1607-5695-1.

Compliance required as indicated.

Due to the present design of the damper trunnion assembly, torque cannot be maintained on the bolt, thereby leading to fretting and fatiguing of the bolt. Although this problem has been partially corrected by replacing the AN 177-34 bolt with S1610-23198 bolt (NAS 627-48 bolt with cotter pin hole), working of the bolt in the assembly has not been completely eliminated. Accordingly, it is considered essential that close surveillance be maintained and the following inspection be carried out pending the development and installation of aredesigned trunnion assembly to correct this difficulty.

During the 50-hour periodic inspection of the damper trunnion for freedom per item No. 20(c) of the Periodic Inspection Check Sheet, Airframe System S-58 Maintenance Manual, remove the damper trunnion bolt P/N S1610-23198 and inspect for condition. If indications of wearing, scouring or fretting are found the bolt must be replaced prior to further flight.

This amendment 39-2140 becomes effective April 8, 1975.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1H11](https://openairdocs.org/tcds/1H11): Centerpointe Aerospace Inc.; names 15 of 15 models: S-58J, S-58FT, S-58C, S-58A, S-58HT, S-58F, S-58G, S-58ET…

## 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: 22 (22 by airframe model, 0 by engine model)
- Makers: Sikorsky 22

Models with the most aircraft:

- [Sikorsky S-58JT](https://openairdocs.org/model/sikorsky-s-58jt): 5 aircraft (airframe model)
- [Sikorsky S-58ET](https://openairdocs.org/model/sikorsky-s-58et): 3 aircraft (airframe model)
- [Sikorsky S-58C](https://openairdocs.org/model/sikorsky-s-58c): 3 aircraft (airframe model)
- [Sikorsky S58E](https://openairdocs.org/model/sikorsky-s58e): 3 aircraft (airframe model)
- [Sikorsky S-58J](https://openairdocs.org/model/sikorsky-s-58j): 2 aircraft (airframe model)
- [Sikorsky S-58H](https://openairdocs.org/model/sikorsky-s-58h): 2 aircraft (airframe model)
- [Sikorsky S-58B](https://openairdocs.org/model/sikorsky-s-58b): 1 aircraft (airframe model)
- [Sikorsky S-58D](https://openairdocs.org/model/sikorsky-s-58d): 1 aircraft (airframe model)
- [Sikorsky S-58BT](https://openairdocs.org/model/sikorsky-s-58bt): 1 aircraft (airframe model)
- [Sikorsky S-58DT](https://openairdocs.org/model/sikorsky-s-58dt): 1 aircraft (airframe model)

All 10 models: https://openairdocs.org/ad/59-16-04/models.md
Every aircraft: https://openairdocs.org/ad/59-16-04/aircraft.md

Its text cites no advisory circulars or STCs.

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