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