Commonwealth legislation

AD/BELL 412/33 - Main Transmission Lower Planetary Spider

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

The directive requires retirement of the main transmission lower planetary spider P/N 412‑040‑785‑101 from Bell 412 helicopters by 2,500 hours TIS or within 100 hours after 2 Feb 1995. It affects operators of those helicopters, who must remove/replace the part, track hours and keep records, bearing the compliance costs. Rationale: fatigue testing showed failures, so a life limit is imposed to reduce in‑service failure risk.

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Current sections

Direct links to the current provisions in AD/BELL 412/33 - Main Transmission Lower Planetary Spider.

AD/BELL 412/33 - Main Transmission Lower Planetary Spider

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Bell Helicopter Textron 412 Series Helicopters

AD/BELL 412/33 Main Transmission Lower Planetary Spider 2/95

Applicability: All Bell Helicopter Textron 412 Series Helicopters with main transmission lower planetary spider P/N 412-040-785-101 installed.

Requirement: Retire the spider from service.

Note 1: FAA AD 94-18-09 Amdt 39-9022 and Bell Alert Service Bulletin ASB 412- 93-72 Revision A refer.

Note 2: The life of Spider P/N 412-040-785-103 is not affected by this AD.

Compliance: Retire the spiders before accumulating 2500 hours time in service or within 100 hours time in service after 2 February 1995, whichever is the later.

Background: Five failures of the main transmission lower planetary spider have been experienced during the manufacturer’s fatigue tests. Accordingly a fatigue life has been established to prevent in service failures.

Source text

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

1 AD/BELL 412/33 - Main Transmission Lower Planetary Spider