# AD 60-11-08: Pilot Bore

- Type: Airworthiness directive
- Status: Current
- Products: Sensenich Propeller Manufacturing 74DM6 and 74DM7
- Effective: November 14, 1961
- Superseded by: Nothing supersedes this AD
- Product type: Propeller
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E48465E076AA83BB862569B3006C3ADE.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/60-11-08

## The airworthiness directive

60-11-08 SENSENICH: Amdt. 166 Part 507 Federal Register May 28, 1960. Applies to M74DM Propellers Installed On Lycoming O-320-B Series Engines Except Propellers With An "A" or "K" prefix to the Serial Number.

Compliance required within the next 100 hours of flight time or by August 1, 1960, whichever comes first, and at each periodic inspection thereafter.

As a result of three incidents of cracked hubs, the following shall be accomplished:

  (a) Remove the propeller and visually inspect for cracks originating in the pilot bore. In case of doubt, any of the approved methods for aluminum alloy inspections should be used. If cracks are found, the propeller shall be retired immediately from service.

  (b) If no cracks are found, polish out any scratches in the bore and break and polish any sharp edges at the front and rear chamfer of the pilot bore.

  (c) When the propeller is reinstalled, torque retaining bolts to 300 inch-pounds.

(Sensenich Service Bulletin No. R-8-1 covers the same subject.)

Revised November 14, 1961.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS P-886](https://openairdocs.org/tcds/P-886): Sensenich Propeller Company; names 2 of 4 models: 74DM6, 74DM7

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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