AD/Bell 427/9 Hydraulic Pump Driveshaft Assembly (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 427/9 Hydraulic Pump - Driveshaft Assembly 5/2009

Applicability:

Bell Helicopter Textron Canada (BHTC) Model 427 helicopters serial numbers 56001 through 56046 and 58001 and 58002.

This AD does not affect helicopters equipped with input shaft part number (P/N)
407-340-107-101 and adapter P/N 407-340-108-101, installed in accordance with Technical Bulletin (TB) 427-05-19 dated 7 January 2005.

Requirement:

1.    Verify the installation of the parts in accordance with BHTC Alert Service Bulletin (ASB) 427-08-22 dated 26 June 2008, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

2.    If any part is missing, install an airworthy input shaft and adapter.

3.    If the parts are correctly installed, make a logbook entry to that effect or attach the serviceable tag to the parts in inventory as per item 6.c. of ASB
427-08-22, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Note:  Transport Canada AD CF-2009-04 dated 22 January 2009 refers.

Compliance:

For all driveshaft assemblies installed on aircraft - At the next driveshaft lubrication, no later than 50 flight hours or 30 calendar days, whichever comes first after the effective date of this AD.

For driveshaft assemblies held as spares - Prior to installation on an aircraft.

This Airworthiness Directive becomes effective on 7 May 2009.

Background:

It has been determined that some hydraulic pump driveshaft assemblies P/N
406-040-072-105 may have been delivered with a missing internal plug or fastening rivet.  This condition, if not corrected, could result in a loss of hydraulic pressure leading to difficulty controlling the helicopter.

This AD mandates a one-time verification of the presence of the plug in the centre of the driveshaft and the rivet that holds the plug in place.

James Coyne
Delegate of the Civil Aviation Safety Authority

26 March 2009