Operators of Airbus A300s and A310s and Boeing 747s, 767s and MD-11s powered by certain models of Pratt &Whitney PW4000 are required to remove the engines before they exceed cyclic time limits set by the US Federal Aviation Administration in a new airworthiness directive (AD). The amended AD follows the 9 March incident in which an Air Sudan A300 lost power on both engines during take-off because of surges in the high-pressure compressors. The AD also requires engines removed from service to be rebuilt to a new standard to prevent surges.
Source: Flight International
