AD/Bell 427/2 Horizontal Stabiliser Auxiliary Fin Assemblies (Cth)
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 39.001(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.
Bell Helicopter Textron 427 Series Helicopters
| AD/BELL 427/2 | Horizontal Stabiliser Auxiliary Fin Assemblies | 4/2006 |
Applicability: | Model 427 helicopters, serial numbers 56001 through 56030 with auxiliary fin assemblies, part numbers 427-035-836-101, -102, -105, or -106, installed. |
Requirement: | Modify auxiliary fin assemblies, part numbers 427-035-836-101, -102, -105, or -106, in accordance with the Accomplishment Instructions in Bell Helicopter Textron (BHT) Alert Service Bulletin 427-01-07, dated 16 November 2001. After accomplishing the modification, reduce the never-exceed-speed (Vne) limitation for a pedal stop failure from 80 knots indicated airspeed (KIAS) to 60 KIAS; by incorporating BHT Rotorcraft Flight Manual BHT-427-FM-2 Revision 5, dated 23 April 2002. Note: FAA AD 2003-04-12 Amdt 39-13061 and Transport Canada AD |
Compliance: | Within 60 days after 13 April 2006, unless already accomplished. |
| This Airworthiness Directive becomes effective on 13 April 2006. | |
Background: | Reports were received of several incidents of main rotor blades contacting the top of the auxiliary fins, resulting in an upper tuning weight coming loose. This Directive requires modification of the overall height of the auxiliary fins to prevent main rotor blade contact, loss of a tuning weight with possible impact with a tail or main rotor blade, and subsequent loss of control of the helicopter. |
David Punshon
Delegate of the Civil Aviation Safety Authority
1 March 2006
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