Pratt & Whitney Canada (P&WC) is conducting an urgent fleet-wide retrofit of compressor rotors in its PW306A and B turbofans. Tests have revealed premature life limits which could cause uncontained engine failures on Galaxy Aerospace corporate jets and Fairchild Dornier 328JET regional airliners.
The company hopes to complete the retrofit, involving around 80 engines, by the third quarter, says president Gilles Ouimet. Around 25% of the fleet has already been fitted with the revised second, third and fourth stage compressor rotor drum assemblies and impeller, he adds.
"We knew this was coming, so we had a new design which we hoped could be implemented during the first engine shop visit. But the original compressor was not going to last as long as we'd hoped, so we had to do this," says Ouimet. He concedes the urgent replacement programme is "quite expensive". The retrofit, mandated in an airworthiness directive by the US Federal Aviation Administration, calls for the removal and replacement of the new parts before exceeding a new P&WC life limit of 3,000 cycles.
The revised design is more durable and features a tie-shaft compressor configuration in place of the original welded design to cope with the cycles flown by business jets and regional airliners.
Source: Flight International
