FAN HUBS FROM six Pratt & Whitney JT8D-200 engines have been removed from service after it was determined that they have the same manufacturing defect believed to have caused the uncontained failure on a Delta Air Lines McDonnell Douglas MD-88 on 7 July. The 25mm-long fatigue crack, which caused the hub to fail, is believed to have resulted from a surface anomaly in a tie-bolt hole. Six other Volvo hubs have the same surface anomaly. The machining distress was noted during inspection following manufacture, but was deemed to be acceptable.
Three of the affected engines belong to Delta, but only two were in service. One was in operation with Continental Airlines, while affected engines owned by Finnair and the Ford Motor Company were in maintenance. According to P&W, it is too early to say whether there are fatigue cracks in any of the hubs which have been removed.
Source: Flight International
