Inspections of SAS Group's grounded Bombardier Q400 turboprop fleet have revealed further instances of corrosion similar to that found on the aircraft that suffered a landing-gear collapse in Denmark on 9 September.

SAS Group has not disclosed how many aircraft are affected. It grounded all 27 aircraft in the Scandinavian Airlines and Widerøe fleets after a second SAS Q400 gear collapse in Vilnius, Lithuania, three days after the Danish accident.

"We have found corrosion in other aircraft," says the carrier. "We are doing all the controls and checks required, and changing all the parts - even on aircraft where nothing has been found."

In the wake of the gear collapses, Transport Canada issued an airworthiness directive calling for the eight Q400 operators worldwide to conduct immediate landing-gear inspections. Bombardier says it is "extremely concerned" by the gear collapses as the type has no history of such events: "These are highly unusual circumstances where two incidents have occurred within such as short space of time."

Lithuanian investigators, having inspected the Vilnius Q400, have found evidence of the same landing-gear actuator failure that was discovered to have affected the Q400 in Denmark.

Representatives of Lithuania's air accident investigation commission are to travel to Copenhagen, says a source in the agency, to perform laboratory examination of the parts in question.

Stockholm's prosecutor has opened a preliminary investigation into SAS Group following the two accidents. No-one was seriously injured in either event, but SAS Group says the prosecutor's case centres on suspicion of "creating danger to another person".

"We reject the claim that there are grounds for the public prosecutor's suspicions," says SAS Group. "We will naturally co-operate with the prosecutor and provide all necessary information."

Source: Flight International