EASA Q400 findings imply isolated fault

 - November 30, 2007, 5:49 AM

The European Aviation Safety Agency last month determined that the failure of the main landing gear of a Scandinavian Airlines Q400 on October 27 did not result from a design flaw, and that the latest incident bore no direct relationship with the two earlier cases that led to the grounding of the airline’s entire fleet of 74-seat turboprops. Scandinavian airworthiness authorities have therefore reissued airworthiness certificates for the type. Nevertheless, as of press time SAS hadn’t reversed its October 29 decision to ground the fleet of 27 airplanes permanently, a move that has so far resulted in the loss of 230 jobs at SAS Sweden.

Preliminary findings by Danish investigators identified a blocked orifice within an actuator assembly as the culprit in the latest accident. The mishap occurred  when Flight SK2867 from Bergen, Norway, landed at Copenhagen International Airport with its right main landing gear only partially extended. The flight carried 40 passengers and four crewmembers, none of whom suffered injuries.

The preliminary report said the blockage prevented the right landing gear from fully extending, implying a cause unrelated to the two earlier incidents that forced SAS to ground its entire fleet in mid-September. However, SAS clearly has determined that it gains more in public good will by grounding the fleet than by attempting to explain the reasons for this, the third accident in two months involving an SAS Q400.

“Confidence in the Q400 has diminished considerably and our customers are becoming increasingly doubtful about flying in this type of aircraft,” said SAS president and CEO Mats Jansson in a written statement.

Fleet Reallocation
According to SAS, the 27 Q400s, including the four that flew for its Wideroe subsidiary, account for some 5 percent of the group’s passenger capacity. SAS said
it would give passengers affected by the grounding the opportunity either to rebook or receive a refund. The airline plans to reallocate aircraft within SAS Group and wet-lease capacity over the next month as a stop-gap measure to compensate for the shortfall. It also plans to dry lease more airplanes over the next three months. SAS added that it expects to implement a long-term solution by the second half of next year.

“The Dash 8 Q400 has given rise to repeated quality-related problems and we can now conclude that the aircraft does not match our passengers’ requirements concerning punctuality and regularity,” said SAS deputy CEO John Dueholm. “SAS’s flight operations have always enjoyed an excellent reputation and there is a risk that use of the Dash 8 Q400 could eventually damage the SAS brand.” 

Bombardier, for its part, “is disappointed with the SAS decision to permanently discontinue flight operations with the Bombardier Q400 given that the landing incident is still under investigation by Danish authorities.”

A Bombardier spokesman told AIN that none of the authorities has drawn any connection between the latest incident and the two others that took place over the past two months. Preliminary findings by Danish civil aviation agency investigators indicated that corrosion inside the actuator piston of the airplane involved in the previous incident, on September 12 in Vilnius, Lithuania, caused the piston to separate from its rod end. Since then SAS had reportedly inspected all its airplanes and, by October 15, had replaced the suspect parts and reactivated the entire fleet.

“Our assessment of this situation, in consultation with Transport Canada, did not identify a systemic landing gear issue,” said the spokesman. “Based on this we advised all Q400 aircraft operators around the world that they should continue normal aircraft operations.” Bombardier says it performed a full review of the landing-gear system with its manufacturer, Goodrich Aerospace, and the results “have confirmed its safe design and operational integrity.”