Commonwealth legislation

AD/PMC/35 Amdt 1 - Propeller Blade Butt Retention Thread - Eddy Current Inspection

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

This directive requires an additional eddy‑current inspection of the tapered thread butt on all threaded McCauley propeller blades, to be done alongside the existing dye‑penetrant check. The inspection technique must be approved by the Secretary; ATG/NDI/EC/5 is given as an acceptable method and test samples are available from the Authority. Operators and maintenance organisations must carry out the eddy‑current check at each propeller overhaul and whenever disassembly allows inspection, because shot‑peened/truncated threads can hide cracks from dye penetrant.

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Current sections

Direct links to the current provisions in AD/PMC/35 Amdt 1 - Propeller Blade Butt Retention Thread - Eddy Current Inspection.

AD/PMC/35 Amdt 1 - Propeller Blade Butt Retention Thread - Eddy Current Inspection

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Propellers - Variable Pitch - McCauley

AD/PMC/35

Amdt 1

Propeller Blade Butt Retention Thread - Eddy Current Inspection

13/88

Applicability: All threaded blade McCauley propellers.

Requirement: In addition to the dye penetrant inspection described in the appropriate McCauley Propeller Service Manual, conduct an eddy current inspection of the tapered thread butt section of the propeller blade in accordance with technique approved by the Secretary.

Eddy Current Technique ATG/NDI/EC/5 constitutes one such technique. Copies of this technique, and test samples may be obtained through regional offices of the Authority.

Compliance: 1. Each time propeller is overhauled.

Whenever propeller disassembly will allow inspection of the blade butt retention threads.

Background: Two recent local failures have occurred at the butt thread section of McCauley propeller blades. One other cracked blade has been detected using eddy current equipment. All subject blades had shot peened and truncated threads. Laboratory tests indicate that the compressive surface formed by the shot peening process may prevent detection of substantial cracks when inspecting with dye penetrants.

This Amendment raised to clarify reinspection requirements.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/PMC/35 Amdt 1 - Propeller Blade Butt Retention Thread - Eddy Current Inspection