AD/PR/32 Amdt 1 Blade Pitch Seizure (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/PR/32 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.
Propellers - Variable Pitch - Dowty Rotol
| AD/PR/32 Amdt 1 | Blade Pitch Seizure | 13/2008 |
Applicability: | All R/354/4-123-F/13, R354/4-123-F/20, R375/4-123-F/21, R389/4-123-F/25, R389/4-123-F/26 and R390/4-123-F/27 propellers fitted to SAAB 340 A or B series aircraft. |
Requirement: | Modify or de-modify (as applicable) the propeller pitch change mechanism in accordance with Dowty Aerospace Mandatory SB SF340-61-88 dated Note: UK CAA AD 002-11-96 dated 2 November 1996 refers. |
Compliance: | Unless previously carried out, incorporate as specified in the Requirement Document paragraph D. |
| This Amendment becomes effective on 18 December 2008. | |
Background: | The manufacturer has advised that during ground running a propeller which had recently been modified to SB SF340-61-79 status, suffered a seizure of the propeller pitch change. This occurred when the slide block, attached to the crosshead by coiled pins, became detached and allowed the crosshead to turn and contact the blade root inner sleeves which then locked the propeller blades in a fixed position. This amendment corrects a typographical error in the background statement with no change to the requirements or compliance sections. The original background statement referred to “coiled springs” instead of “coiled pins”. The original issue of this AD became effective on 27 March 1997. |
James Coyne
Delegate of the Civil Aviation Safety Authority
6 November 2008
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