Document ID: chunk:federal_register_of_legislation:F2009L03830:body:0:p2
Version: federal_register_of_legislation:F2009L03830
Segment Type: other
Provision Reference: 
Character Range: 2842–4378

this AD, unless previously accomplished.

             For Requirement 4 - Upon completion of SB 84-29-22, initial issue, dated
             5 December 2008, Revision A, or later revision approved by the Chief, Transport Canada.
             This Amendment becomes effective on 19 November 2009.
Background:  Several cases have been reported where a loss of fluid in the No.2 hydraulic system has caused the power transfer unit (PTU) to over speed, resulting in pressure fluctuations and increased fluid flow within the No.1 hydraulic system.  In one case, the hydraulic system control logic did not shut down the PTU and the over speed condition persisted, resulting in the illumination of the No.1 HYD FLUID HOT caution light.

             As an interim action to avoid possible loss of both the No.1 and No.2 hydraulic systems, the AFM has been revised to include pulling the HYD PWR XFER circuit breaker in the event of the loss of all hydraulic fluid in the No.2 hydraulic system.

             Amendment 1 of this AD mandates modification of the PTU control logic, including the provision of automatic PTU shutdown in the event of loss of fluid in the No. 2 hydraulic system.  In addition, the applicability of the AD has been revised to remove aircraft S/N 4185 and subsequent, since an equivalent modification has been installed in production on these aircraft.

             The original issue of this AD became effective on 31 May 2006.

David Villiers
Delegate of the Civil Aviation Safety Authority

28 September 2009