Pratt & Whitney Canada is rushing to complete certification of an improved compressor blade-cooling system to counter reliability problems on the PW306B-powered Dornier 328JET. The problems have particularly hit Atlantic Coast Airlines (ACA), which has experienced an engine replacement rate "20 times higher" on its 30-strong 328JET fleet than on its General Electric CF34-powered Bombardier CRJ fleet, says the airline.

P&WC says that "an engine upgrade is currently being implemented to further enhance durability of the compressor blade, and it will be available in the second quarter of 2004". It adds that "the cooling scheme for the compressor blade may not be performing in a way which provides the optimal durability P&WC wants in all cases." To address this, the company has developed sophisticated inspection methods that enable it to determine the wear on the blade.

Early diagnostics have resulted in engines being taken off-wing sooner than expected, thereby creating a shortage in hardware availability. Although several failures have been experienced, none of the ACA removals resulted from in-flight shutdowns.

Source: Flight International