COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters AD/BELL 407/12 Crew Seat Belt and Restraint Assembly 13/99 Applicability: BHTC Model 407 helicopters, serial numbers 53000 through 53342 and 53344. Requirement: Replace the crew seat restraint assemblies with new ones, part number 222-320-823- 129, as per BHTC Alert Service Bulletin 407-99-29, dated 10 May 1999. Note: Transport Canada AD CF-99-25 refers. Compliance: Before 31 December 2000, unless already accomplished. This Airworthiness Directive becomes effective on 30 December 1999. Background: The lap portion of a crew seat belt can in some circumstances lose tension as a result of slippage, and may be difficult to release using one hand in emergency situations. To correct the problem, BHTC introduced improved crew seat belt and restraint assemblies with non-slippage features, meeting the latest standard. The rotary buckle is replaced with a buckle that allows for easier release with one hand.