# AD 78-05-01: Fuel Bypass Lines

- Type: Airworthiness directive
- Status: Current
- Products: Sikorsky S-58BT, S-58DT, S-58ET, S-58FT, S-58HT and S-58JT
- Effective: March 31, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-3146
- Registered aircraft: 10 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/5BC5F9FA3FEF13EE86256A56004B066A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-05-01

## The airworthiness directive

78-05-01 SIKORSKY AIRCRAFT: Amendment 39-3146. Applies to all Model S-58T series helicopters.

Compliance required prior to May 25, 1978.

To preclude possible fuel starvation of the PT6T-3 and PT6T-6 engines resulting from oil-to-fuel heater contamination, relocate the impending fuel bypass sensor lines on both engine power sections in accordance with the instructions set forth in Part II, Paragraph A, of Sikorsky Service Bulletin No. 58B30-12C, dated January 12, 1976.

This amendment becomes effective March 31, 1978.

## 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 6 of 15 models: S-58FT, S-58HT, S-58ET, S-58DT, S-58BT, S-58JT

## 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: 10 (10 by airframe model, 0 by engine model)
- Makers: Sikorsky 10

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-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 4 models: https://openairdocs.org/ad/78-05-01/models.md
Every aircraft: https://openairdocs.org/ad/78-05-01/aircraft.md

Its text cites no advisory circulars or STCs.

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