CEN20LA269

During an aerial application flight, the pilot was returning to the airplane’s base when the engine "spooled down” and lost total power. The pilot stated that, when the total loss of engine power occurred, the airplane was established in cruise flight at an altitude of about 400 ft above ground level. He was unable to restore engine power by moving the power and propeller levers to full forward and activating the fuel boost pump and ignitors. The pilot made a “firm” forced landing in an open field. The airplane made a ground loop, which caused the tailwheel to separate and resulted in substantial damage to the aft fuselage. Postaccident examination of the fuel system revealed ample fuel remaining and no evidence of contamination. The engine operated normally during two postaccident ground tests. Thus, the reasons for the total loss of engine power during the accident flight could not be determined with the available evidence from the investigation.

On July 3, 2020, about 1700 central daylight time, an Air Tractor AT-602 airplane, N602NY, was substantially damaged when it was involved in an accident near Weldon, Arkansas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. The pilot stated that he departed from a private airstrip with about 75 gallons of Jet A fuel and a load of dry granular fertilizer. The pilot reported that the aerial application portion of the flight was uneventful but that, about 10 minutes into the flight, as the airplane was returning to its base, the engine "spooled down" and the airplane had a total loss of engine power. At the time, the airplane was about 3 miles from the airstrip and was established in cruise flight about 400 ft above ground level. The pilot was unable to restore engine power by moving the power and propeller levers to full forward and activating the fuel boost pump and ignitors. He did not recall looking at the cockpit engine gauges after the loss of engine power. The pilot stated that he made a “firm” forced landing in an open field but lost directional control of the airplane. The aft fuselage sustained substantial damage when the tailwheel separated during the ground loop. Three days after the accident, before notifying the National Transportation Safety Board (NTSB) or Federal Aviation Administration (FAA) of the accident, the pilot’s aviation mechanic examined the airplane at the accident site to begin a repair estimate. The mechanic stated that ample fuel was in the fuel tanks and that he was able to start and run the engine at the accident site. The mechanic noted that the engine responded to his power lever inputs and that his movement of the propeller lever cycled the propeller without any anomalies with an rpm of 1,500. The mechanic stated that all observed engine parameters were nominal during the engine test run. The FAA and the NTSB were subsequently notified about the accident. The airplane was partially disassembled and recovered from the field to a repair station for repairs and examinations. The recovery crew reported that about 56 gallons of fuel was drained from the wing tanks and that the recovered fuel was evenly distributed between the wing fuel tanks. Subsequent examination of the airplane revealed that the fuel lines, fuel tank inlet screens, and fuel filters showed no evidence of any blockage, water, or significant particles. The airplane's digital fuel management system indicated that 50.3 gallons of fuel remained in the fuel tanks after the postaccident engine test run at the accident site. A second engine ground test was completed in the presence of a FAA maintenance inspector after the airframe was repaired. The engine started and operated without any anomalies during the ground test. Additional testing did not reveal any anomalies with the mechanical airframe fuel pump, electric fuel boost pump, or engine Py line. The engine hadaccumulated 1,521.6 hours since new and 141 hours since its last inspection on May 1, 2020.