Pratt & Whitney has been forced to recall thousands of high pressure turbine (HPT) blades and remove eight engines from service after a new ultrasonic cleaning device caused microscopic cracking of the blades.
The company declines to comment on the cost of the problem, but it is known to "run into millions of dollars", say industry sources.
The problem affects about 8,200 HPT blades that were processed in the cleaning machine between 17 January and 26 February. P&W inspectors became suspicious of the device, which cleaned first and second stage HPT blades for JT9D, PW2000, PW4000 and International Aero Engines V2500s, when they saw "-a blade come out with cracks that they'd never seen before", says P&W.
The company says the device had been "mis-calibrated" and caused microscopic surface cracks on the inside of the hollow blades.
Further investigations led P&W to issue an all-operators warning on 17 March, instructing them to "remove forthwith" affected blades and take aircraft with suspect engines "to a maintenance base as soon as possible".
By 24 March, the company had accounted for all the affected blades and determined that, of the 8,200 suspect blades, some 4,800 did not leave its inventory storage area at North Haven, Connecticut. Of the rest, some 3,400 were still in operators' inventories, and "-only eight engines had to be taken out of service", says P&W.
Source: Flight International
