This Special Airworthiness Information Bulletin (SAIB) informs registered owners/operators of all

Air Tractor, Inc. Models AT-400, AT-400A, AT-402, AT-402A, and AT-402B airplanes (under

Type Certificate Data Sheets A9SW and A17SW) of an airworthiness concern. Specifically, this

SAIB provides for general and detailed inspection for fatigue cracking of the engine mount tube.

At this time, this airworthiness concern has not been determined to be an unsafe condition that would

warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations

(14 CFR) part 39.