On August 8, 2011, approximately 0530 mountain standard time, an Air Tractor AT-602, N5123L, sustained substantial damage when it impacted a tower while maneuvering near Willcox, Arizona. The commercial pilot, the sole occupant of the airplane, received minor injuries. M and J Bailey, Inc., Dalhart, Texas, was operating the airplane under the provisions of 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed for the early morning aerial application flight, which had originated about 15 minutes before the accident. A flight plan had not been filed. The pilot reported that he was performing a calibration pass on his target field at an altitude of about 60 feet above ground level when the airplane struck an unmarked 80-foot-tall tower. The airplane's engine caught fire and lost power. During the forced landing sequence, the airplane struck a fence, which damaged the left wing. According to the pilot, the tower had recently been installed without his knowledge.