Follows In-Flight Failure Of Flap Torque Tube

The FAA has issued a Special Airworthiness Information Bulletin (SAIB) for owners, operators, maintenance technicians, and inspectors related to an airworthiness concern for Air Tractor, Inc. (Air Tractor) Models AT-802/802A/602/504/503/503A/502/502A/502B/501/402/402A/402B /401/ 401A/ /401B/400/400A/302/301/300/250 airplanes (under Type Certificate Data Sheets A9SW, A17SW, and A19SW).

Specifically, this SAIB provides inspection procedures and on-condition maintenance actions for the flap torque tube for affected airplanes.

Air Tractor, Inc. recently issued Snow Engineering Co. Service Letter (SL) #347 for all the above-referenced models of Air Tractor airplanes. The SL was issued after in-flight failure of the flap torque tube on a Model AT-802A airplane. Failure of the welds attaching the flap actuator brackets to the torque tube resulted in uncommanded retraction of both flaps. One other crack in a flap torque tube bracket weld was reported for a Model AT-502B airplane in 2007. The SL provides owners and operators instructions for inspection of the torque tube attach brackets for cracks in the welds and replacement of the torque tube if cracks are found. SL #347 also requests that you report any cracks you find to the Air Tractor Customer Service Department using the contact information provided.

The FAA recommends inspection of the flap torque tube using the procedures in SL #347 and a report of any cracks found to the Air Tractor Service Department.

(Image from file)

FMI: SAIB