AD/PC-12/51 Main Landing Gear Special Bolts (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.

Pilatus PC-12 Series Aeroplanes

AD/PC-12/51 Main Landing Gear Special Bolts 11/2007

Applicability:

All Model PC-12, PC-12/45 and PC-12/47 aircraft, with Manufacturer Serial Number 101 through MSN 749; equipped with MLG assemblies and special bolts as listed below:

MLG assemblies part number, 532.10.12.037, 532.10.12.038, 532.10.12.041, 532.10.12.042, 532.10.12.043, 532.10.12.044, 532.10.12.047, 532.10.12.048, 532.10.12.049. 532.10.12.050, 532.10.12.051 and 532.10.12.052 delivered before
31 December 2006; and held as a spare.

Special bolts part number 532.10.12.110, 532.10.12.205. 532.10.12.077 and 532.10.12.202 delivered before 31 December 2006; and held as a spare.

Modification kit numbers 500.50.12.267, 500.50.12.286, and 500.50.12.299 delivered before 31 December 2006; and held as a spare.

Requirement:

1.    Perform an inspection of the special bolts that attach the MLG retraction actuators and the special bolts that attach the shock absorbers to the MLG assemblies to identify the serial numbers that start with the letters AT or have a supplier code AT; in accordance with paragraph 3.A. of PILATUS PC-12 Service Bulletin (SB) No. 32-020.

If affected bolts are identified during the above inspection, before further flight, replace the affected special bolts with new bolts with new part numbers; in accordance with paragraph 3.B. of SB No. 32-020.

2.    Perform an inspection of applicable MLG assemblies held as spares, special bolts held as spares, and modification kits incorporating special bolts held as spares in accordance with paragraph 4. of SB No. 32-020.  If affected bolts are identified, replace the affected special bolts.

Note:  Switzerland FOCA AD HB-2007-382 refers.

Compliance:

For Requirement 1 and 2:  Within 100 hours time in service or 3 months after
25 October 2007, whichever occurs first.

This Airworthiness Directive becomes effective on 25 October 2007.

Background: The manufacturer has determined that certain main landing gear bolts may be affected by hydrogen embrittlement.  Bolts in this condition that are installed in the main landing gear have a decreased fatigue life, and unless detected and corrected, could lead to main landing gear collapse during operation.

David Villiers
Delegate of the Civil Aviation Safety Authority

7 September 2007