Valve failure led to 2011 runway excursion of Challenger 300 in Iqaluit, Nunavut

DORVAL, QC, Jan. 8, 2014 /CNW/ - The Transportation Safety Board of Canada (TSB) today released its investigation report (A11Q0052) into the March 2011 runway excursion of a Bombardier BD100-1A10 in Iqaluit, Nunavut.

On 12 March 2011, the Bombardier BD100-1A10 (commercially known as a Challenger 300), operated by Tri Marine Management Company LLC, departed Long Beach, California, for Iqaluit, Nunavut, with 2 crew members and 1 passenger on board. The aircraft landed in Iqaluit on Runway 35 at approximately 2100 Eastern Daylight Time. Upon touchdown, the nose wheel veered to the right and attempts to control the uncommanded veer were unsuccessful. The aircraft left the runway, travelled 400 feet over frozen ground and stopped approximately 100 feet from the edge of the runway in a snow bank. There were no injuries, and aircraft damage was limited to the nose and main landing gear.

The investigation found that the electro hydraulic servo valve (EHSV) did not respond to steering commands, and the steering selector valve did not close. These conditions prevented the nose-wheel steering system from responding appropriately and blocked the steering pointing to the right. This EHSV failure was likely due to contamination, internal corrosion, and exposure to cold temperatures.

Bombardier conducted a series of tests and is in the process of issuing a service bulletin to require a one-time check of the EHSV electrical servo motor. Bombardier has also introduced a new EHSV configuration that has an O-ring seal between the connector and valve cap to seal from moisture ingress.

The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

SOURCE Transportation Safety Board of Canada

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