# AD 68-26-01: Lower Coupling Drive Shaft

- Type: Airworthiness directive
- Status: Current
- Products: Schweizer 269A, 269A-1 and 269B
- Effective: December 21, 1968
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-696
- Registered aircraft: 134 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4C44211DCF81B4A486256A38006B9D0A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/68-26-01

## The airworthiness directive

68-26-01 HUGHES: Amendment 39-696. Applies to Model 269A Helicopter Serial Nos. 0011 through 0893 (except TH-55A helicopters), 269A-1 Helicopter Serial Nos. 0001 through 0041, 269A-2 Helicopters Serial Nos. 0001 and 0002, 269B Helicopter Series Nos. 0001 through 0359 with P/N 269A5504-3 Lower Coupling Drive Shaft or Hughes P/N 80-269A5504-5 or P/N 269A5504-5 Lower Coupling Drive Shaft assembly installed.

Compliance required within 25 hours of helicopter operation after the effective date of this airworthiness directive, unless previously accomplished.

To prevent failures of the lower coupling drive shaft (Hughes P/N 269A5504-3) or lower coupling drive shaft assembly (Hughes P/N 80-269A5504-5 or 269A5504-5) by assuring the physical integrity of the shaft, including freedom from cracks:

  (a) Inspect the entire shaft per Hughes Service Information Notice No. N-55.1, dated December 9, 1968, or later FAA approved revisions, or any equivalent inspection approved by the Chief, Aircraft Engineering Division, Western Region.

  (1) If cracks are found during this inspection, retire shaft from service and replace with a new shaft.

  (2) If no cracks are found, identify the shaft per Item "m" of Hughes Service Information Notice No. N-55.1, or later FAA approved revisions, or equivalent identification approved by the Chief, Aircraft Engineering Division, Western Region. The shaft may continue to be used in accordance with service life limitations.

  (b) Determine that the inspection or identification, as appropriate, specified in paragraph (a) has been accomplished, prior to installing replacement lower coupling drive shafts (P/N 269A5504-3).

This supersedes Amendment 39-661 (33 F.R. 14636), AD 68-20-03.

This amendment becomes effective December 21, 1968.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4H12](https://openairdocs.org/tcds/4H12): Schweizer RSG LLC; names 3 of 6 models: 269B, 269A-1, 269A

## 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: 134 (134 by airframe model, 0 by engine model)
- Makers: Hughes 133, Schweizer 1

Models with the most aircraft:

- [Hughes 269A](https://openairdocs.org/model/hughes-269a): 97 aircraft (airframe model)
- [Hughes 269B](https://openairdocs.org/model/hughes-269b): 31 aircraft (airframe model)
- [Hughes 269A-1](https://openairdocs.org/model/hughes-269a-1): 5 aircraft (airframe model)
- [Schweizer 269A](https://openairdocs.org/model/schweizer-269a): 1 aircraft (airframe model)

All 4 models: https://openairdocs.org/ad/68-26-01/models.md
Every aircraft: https://openairdocs.org/ad/68-26-01/aircraft.md

Its text cites no advisory circulars or STCs.

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