A seal issue caused the engine failure that kept the Bombardier CSeries jet from its debut at this week's Farnborough Airshow in England, a Pratt & Whitney official said.
"The issue is a seal problem in the oil system. The fan-drive gear system is rock solid," Pratt Commercial Engines President David Brantner told reporters in England on Sunday at a briefing the day before the Farnborough Air Show opened.
The Bombardier CSeries, a single-aisle jet, is the first platform for the next generation of Pratt's commercial engines known as PurePower. The engines have an innovative geared-fan design that provides significant fuel savings.
When the engine caught fire, debris shot out of the casing, damaging the aircraft, which was on the ground in testing at the time, reports said. No one was hurt.
Pratt President Paul Adams told the Bloomberg news service on Sunday that Pratt is working on "minor modifications to the engines" and that flight testing should resume in the next few weeks.
"We made a modification to the oil system and we are performing validation testing at this time," a Pratt spokesman said Monday in an e-mail from England. "The fundamental architecture of the Geared Turbofan engine remains sound. As soon as we have completed our evaluation of the validation testing we will have a better estimate of when flight testing can resume."
The spokesman noted that the PurePower is further along in development than General Electric's next generation engine, the LEAP-1. Airbus customers will be able to choose either the LEAP-1 or the PurePower engine when they buy A320neos, a plane scheduled to go into service at the end of 2015, the same time as the CSeries.
"Incidents like these are not uncommon in engine development," said Richard Aboulafia, an analyst with the Teal Group.
Rolls-Royce's Trent 1000 blew up on a test bed in 2010 because of an oil fire. That engine is on the Boeing Dreamliner. General Electric's uncontained engine failure during a taxi test on the Dreamliner in 2012 was caused by failure of a fan shaft.
Aboulafia said that while the explosion was bad timing for Bombardier, he said the fact that the CSeries couldn't fly at Farnborough wouldn't matter much in making the program a success or failure.
Bombardier announced Sunday that it has 48 letters of intent, though not firm orders, from a British firm that leases planes to small airlines in Eastern Europe, a regional Chinese airline, and a low-cost airline in Jordan.
Aboulafia said that from Pratt's perspective, being chosen as the sole engine on the CSeries was mostly important in convincing Airbus and Embraer to embrace the new design on those companies' single-aisle jets.
The A320neo is supposed to start flight testing in September. A Pratt spokesman said the company doesn't anticipate this CSeries problem will delay the A320 testing program.