EASA SIB CE-11-57
Air Tractor, Inc. AT-400 and AT-402 Series Aeroplanes — Engine Mount Section
Summary
The Special Airworthiness Information Bulletin SAIB: CE-11-57 is an FAA informational bulletin addressing an airworthiness concern for Air Tractor, Inc. Models AT-400, AT-400A, AT-402, AT-402A, and AT-402B airplanes. It highlights the need for inspections of the engine mount attach tubes for fatigue cracking, particularly at the left hand firewall attach location, but does not mandate regulatory action. The bulletin provides guidance on inspection procedures and reporting for affected aircraft under Type Certificate Data Sheets A9SW and A17SW.
What Changed
This bulletin introduces a recommendation for recurring visual inspections of the engine mount attach tubes at the firewall on specified Air Tractor AT-400 and AT-402 series airplanes. It responds to a reported fatigue crack found in the engine mount tube weld area and directs operators to follow inspection procedures outlined in Snow Engineering Co. Service Letter #297. No new airworthiness directive or mandatory action is issued at this time.
Why It Matters
This information is important for aviation professionals because undetected fatigue cracks in the engine mount attach tubes can compromise structural integrity and safety. Operators and maintenance personnel need to be aware of the potential for cracking and conduct inspections to prevent possible failure. Early detection and repair help maintain aircraft airworthiness and avoid costly structural damage or unsafe conditions.
What To Do
Owners and operators of Air Tractor Models AT-400, AT-400A, AT-402, AT-402A, and AT-402B should perform initial and recurring inspections of the engine mount attach tubes as specified in Snow Engineering Co. Service Letter #297. Any cracks found must be repaired or replaced following Air Tractor's service instructions before further flight. Additionally, operators are encouraged to report any findings of cracks to the FAA using the contact information provided.
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