Bombardier's Q400 airplane.
U.S. air authorities have issued a safety directive aimed at preventing potentially dangerous stalls of Bombardier Inc.'s Q400 turboprop commuter airplane.
The directive was sent out Thursday to U.S. airlines that operate 69 of the planes.
It follows on a similar airworthiness directive by Transport Canada in February, which was issued following a request from Montreal-based Bombardier.
There are 288 Q400s being flown by 30 operators around the world, said Bombardier commercial aircraft spokesman John Arnone.
Federal Aviation Administration spokesman Les Dorr said the directive orders the airlines to inspect a key nose-mounted flight-monitoring component that plugs into the plane's stall-protection system and that could malfunction under icy conditions.
Planes in icy conditions can become difficult to handle and are prone to stalling at lower-than-normal speeds.
There have been no reported incidents or accidents related to the component in question.
The directive is not unusual, said Mr. Dorr. "We issue probably about 250 to 300 airworthiness directives every year on airplanes and airplane systems," he said in an interview.
"It's not uncommon."
The airlines receiving the directive have been instructed to inspect the part and to replace it if it is found not to be up to standard, he said.
Mr. Arnone said the issue was brought to Bombardier's attention by a supplier after it discovered the problem on another, non-Bombardier, aircraft.
Bombardier put out a service bulletin to Q400 operators last fall and that was followed up by the Transport Canada directive in February, he said.
A Bombardier Dash 8-Q400, operated by Colgan Air Inc., crashed in Buffalo, N.Y. last year after it entered a stall in icy conditions and the flight crew failed to recover. All 49 aboard as well as one person on the ground were killed. But pilot error rather than system failure was blamed.