Applicability: Bombardier Inc. Models DHC-8-400, DHC-8-401 and DHC-8-402 aeroplanes, Serial Numbers 4001, 4003 and subsequent.

Requirement:

1. Amend the Aeroplane Flight Manual (AFM), PSM 1-84-IA, by inserting Temporary Amendment (TA) No. 13, dated 14 July 2005, or later approved changes to this AFM temporary amendment.

2. Advise all flight crew of the changes introduced by the AFM temporary amendment.

Note: Transport Canada AD CF-2006-08 dated 26 April 2006 refers.

Compliance: Within 14 days after the effective date of this directive.

This Airworthiness Directive becomes effective on 31 May 2006.

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.

FMI: www.casa.gov.au