Emergency AD: Falcon 50 fire extinguishing system inspection

February 21, 2011

The European Aviation Safety Agency (EASA) issued an emergency airworthiness directive, requiring inspection of the fire extinguishing system of Dassault Falcon 50 and Falcon 50EX aircraft.

On two occurrences on Falcon 50 aeroplanes in service, it was detected that two pipes had been swapped in maintenance at the frame 42 firewall. The swapped lines are the extinguishing system line to engine # 2,and engine # 2 Low Pressure (LP) bleed line.

If the swapping of these two lines is not detected and corrected, in case of engine # 2 fire, the fire extinguishing capability would not be operational.

For this reason, the AD requires an inspection of the connection of the two lines (extinguishing and LP bleed lines) at frame 42 in the rear compartment and, in case of findings, proper re-installation of the lines. This AD requires as well reporting to Dassault Aviation. This AD is considered to be an interim measure and, depending on the inspection results provided by operators, further AD action may follow.



Emergency AD: Checks ordered of DHC-8-400 MLG alternative extension system

January 19, 2011

Transport Canada issued an emergency airworthiness directive, ordering of the DHC-8-400 MLG alternative extension system.

Transport Canada reported that two cases of main landing gear (MLG)  alternate extension system (AES) cam mechanism failure were found during line  checks.

The cam mechanism operates the cable to open the MLG door and releases the MLG uplock in sequence. In the case where it is necessary to deploy the MLG using the AES, the failure of the MLG AES cam mechanism on one side will lead to an unsafe asymmetrical landing configuration. Preliminary investigation indicates that the cam mechanism failure may have occurred and remained dormant after a previous AES operation. The cam mechanism may not have fully returned to the normal rested position. With the cam mechanism out of normal rested position, normal powered landing gear  door operation could introduce sufficient loads to fracture the cam mechanism or rupture the door release cable.

The AD mandates the initial and subsequent inspections for proper operation of the MLG AES cam mechanism on DHC-8-400 Series aircraft, and rectify as necessary.



EASA issues emergency AD for Airbus A300-600 pitch uncoupling unit inspections

November 19, 2010

The European Aviation Safety Agency (EASA) issued an emergergency airworthiness directive (EASA EAD 2010-0239-E)  mandating an inspection of Airbus A300-600 pitch uncoupling units.

During a routine maintenance check on an A300-600 aeroplane, the operator found the pitch uncoupling unit installed at an incorrect location.
The pitch uncoupling unit was inverted with the rod assembly.

After a complete inspection of all A300-600 aeroplanes of its fleet, the operator identified the same incorrect installation on another aeroplane.

Had this routine maintenance check, which was accomplished for other purposes, not been carried out, the incorrect installation could only have been detected during the accomplishment of the pitch uncoupling functional test.

This condition, if not detected and corrected, in combination with particular failure modes, could lead to loss of control of the aeroplane during the takeoff phase.

For this reason, the AD requires a one time visual inspection, to detect any incorrect installation of the pitch uncoupling unit, and, depending on findings, to take corrective actions.

The AD applies to A300-600 aeroplanes, all certified models, all serial numbers, and A300F4-608ST aeroplanes, all serial numbers, except aeroplanes on which the pitch uncoupling functional test has already been performed in service since new.


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