AD/Cresco/9 MLG Lower Torque Links (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.

Pacific Aerospace Corporation Cresco Series Aeroplanes

AD/CRESCO/9 MLG Lower Torque Links 2/2007

Applicability:

Model 08-600 aircraft on restricted category agricultural operations, fitted with main landing gear (MLG) lower pivot torque link bolts part number (P/N) NAS 1307-78D.

Requirement:

1.    Inspect the MLG torque link assemblies for wear in accordance with the maintenance schedule in Chapter 05-10-00 page 615, and the MLG wear limits in Chapter 32-10-00 page 601, of Pacific Aerospace Corporation (PAC) Cresco
08-600 Maintenance Manual.

Replace or rework worn parts as required, before further flight.

Replace a worn lower torque link assembly P/N 08-40091-1, or incorporate MOD PAC/CR/0435, before further flight.

2.    Remove the MLG lower pivot torque link bolt in accordance with Chapter 32 of the PAC Cresco 08-600 Maintenance Manual.

a.     Inspect the lower pivot torque link bolts using an approved direct or indirect magnetic particle inspection method that is equivalent to ASTM International Standard No. E-1444.

Replace cracked bolts before further flight.

b.    Re-assemble and lubricate the lower torque link assembly in accordance with Chapters 32 and 12 of PAC Cresco 08-600 Maintenance Manual.  Torque the MLG lower pivot torque link bolts 180 to 210 inch-pounds.

Note 1:  ASTM Standard No. E-1444 establishes minimum requirements for magnetic particle inspection examination used for the detection of surface or slightly subsurface discontinuities in ferromagnetic material.

Note 2:  MOD PAC/CR/0300 is the installation of alternate lower torque link bolts and torque plate assemblies.

Note 3:  MOD PAC/CR/0435 introduces replaceable bushes in accordance with PAC Drawing 08-03179.  Lower torque link assemblies P/N 08-40091-1 can be reworked and re-identified as P/N 08-40031-4 if the wear damage does not exceed the rework dimensions in PAC Drawing 08-03179.

Note 4:  NZ CAA AD DCA/CRESCO/9 refers.

Compliance:	Within 150 hours time in service after 15 February 2007 or before MLG lower pivot torque link bolts exceed 300 hours time in service, whichever occurs later.  Inspect thereafter at intervals not to exceed 300 hours time in service.
This Airworthiness Directive becomes effective on 15 February 2007.
Background:	The NZ CAA received a substantial number of reports of Cresco 08-600 MLG lower torque link bolts with cracks under the bolt head.  The currently installed bolt does not appear to be adequate for all working applications.  This Directive requires inspection of the MLG torque link assemblies and MLG lower pivot torque link bolts.

David Villiers
Delegate of the Civil Aviation Safety Authority

5 January 2007