DORVAL, Que.—The Transportation Safety Board has shed light on what caused a fire during ground tests of Bombardier’s CSeries passenger jet two years ago.
The independent agency says there was a seal failure on an oil feed tube in the left engine of the CS100 plane during the May 29, 2014, incident at Montreal’s Mirabel airport.
The safety board says the malfunction led to a failure of a turbine rotor and a subsequent fire, which was extinguished by Bombardier ground personnel.
Nobody was hurt during the incident—two pilots and four test engineers were able to evacuate the aircraft safety—but the engine and the aircraft sustained substantial damage.
Bombardier grounded the CSeries test aircraft until the cause of the fire was determined, causing concerns among investors who were already skeptical about delays to the commercial jet program.
The TSB says engine supplier Pratt & Whitney has revised the cool-down procedure and made other changes to prevent a recurrence of the overheating that caused the seal to fail.
With its first commercial plane poised to take to the skies, the CSeries program is two and a half years behind schedule and at least $2 billion above cost estimates. Swiss International Air Lines took possession of the first CS100 June 29 and is scheduled to put the plane into regular service July 15.