AD/UH-1/13 - 42 degree Gearbox (Cth)

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

Bell UH-1 Series Helicopters

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

AD/UH-1/13 42° Gearbox 8/2000

Applicability: Model UH1A, UH1B, UH1E, UH1F, UH1H, UH1L, UH1P, TH1F and TH1L with 42° gearbox P/N 204-040-003-023 or -037 installed.

Requirement: Action in accordance with the technical requirements of FAA AD 95-10-08.

Compliance: Before further flight after the effective date of this directive, thereafter at intervals not exceeding 400 torque events; where a torque event is defined as:

* a takeoff or a lift (internal or external).

This Airworthiness Directive becomes effective on 10 August 2000.

Background: There have been a high number of accidents related to 42° gearbox failures. Investigation has found that the normal operating regimes of the helicopters exceed the number of torque events that were anticipated during the certification process. Any operations outside the limits specified in the flight manual will accelerate drive train and gearbox failure.