AD proposed for TFE731 turbine disks

 - July 24, 2007, 11:07 AM

The FAA is accepting comments until August 16 on a proposed Airworthiness Directive that would affect as many as 3,572 TFE731-2 and -3 turbofans on U.S.-registered aircraft. If the measure is enacted, the engines’ low-pressure turbine stage 1 disks would have to be repetitively checked for fatigue cracks. An estimated 1,900 of those engines would require disk replacement under the proposed AD. As written, the directive mandates compliance with a two-year-old Honeywell Service Bulletin that addresses possible fatigue cracking in the disks. The SB is based on three uncontained failures involving the disks that have occurred over the past 16 years. Replacement parts are estimated to cost about $30,000 per engine. The original SB required the work to be done by “certain approved repair stations” but the proposed AD will permit work “by any station certified to perform the repair.” To comment on the proposal, call Joseph Costa at (562) 627-5246.