Lycoming has issued Mandatory Service Bulletin 569, which effectively “retires” – to use Lycoming’s word – more than 5,000 crankshafts that the company suspects may be faulty.
“Lycoming has continued to analyze crankshafts in service,” the bulletin states. “While there have been no failures in the crankshafts which are the subject of this Service Bulletin, as part of our commitment to quality, Lycoming is initiating a crankshaft retirement program.”
The program requires removal of the specified crankshafts “when the crankcase is separated or at overhaul,” whichever occurs first, but not later than Feb. 21, 2009. Lycoming is offering a crankshaft kit to affected owners for $2,000. It includes the crankshaft and all necessary bearings, gears, pins, plugs, piston rings, washers, seals and gaskets, but the cost of assembly and reinstallation must be borne by owners.
The “retirement” covers a range of engines in the -360, -390, -540, -580 and -720 series, but excludes all that already have complied with Service Bulletins 552, 553, 566 or Supplement 1 to SB 566; and new, rebuilt, overhauled or repaired engines shipped to their owners by Lycoming after July 11, 2005.
Lycoming does not say whether the latest round of recalls finally withdraws all crankshafts forged by Interstate Southwest Ltd., which Lycoming insists were overheated in the forging process and non-conforming. However, Lycoming General Manager Ian Walsh told GAN in January that “Lycoming monitors the performance of all crankshafts forged by Interstate, looking for changes in performance.”
The full text of the 56-page Service Bulletin can be found at Lycoming.Textron.com/Support/Publications/MaintenancePublications/ServiceBulletins/SB569.pdf.