AD/BN-2/35 Amdt 3 Airframe Structural Fatigue Life Limitation (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BN-2/35 Amdt 2 and issues the following AD under subregulation 39.001(1) of CASR 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.

Pilatus Britten-Norman BN-2 Series Aeroplanes

AD/BN-2/35 Amdt 3 Airframe Structural Fatigue Life Limitation 16/2010

Applicability:

All BN-2 piston engine models.

Requirement:

Retire from service the wing and wing attachment fuselage frames.

Compliance:

Before 30,000 hours total time in service (for BN-2A model with 49 foot wingspan).

Before 28,000 hours total time in service (for BN-2B model).

This Amendment becomes effective on 9 August 2010.

Background:

This amendment increases the retirement life from 28,000 hours to 30,000 hours based on advice from the manufacturer for the BN-2A model only.  Recent fatigue data analysis indicates the fatigue life can be safely increased to 30,000 hours for the BN-2A model with 49 foot wingspan, pending further review by the manufacturer.

Finalised fatigue lives for the BN-2A and BN-2B models will be provided once Pilatus-Britten Norman have completed their review of fatigue for these variants.

The fatigue life for the BN-2T is contained in the maintenance manual, section 4.3 “Wing Structure Safe Life” and is based on utilisation rate.

Mike Higgins
Delegate of the Civil Aviation Safety Authority

5 August 2010