CEN22LA085

The pilot reported that immediately after takeoff, both propeller assemblies went into a feathered condition. The pilot was able to maneuver the airplane back to a runway. After a hard landing, the left tire blew, the airplane exited the runway, and the airplane’s left wing sustained substantial damage. On the day before the accident flight, the airplane underwent maintenance to troubleshoot a propeller autofeather issue. A mechanic tested the autofeather system and replaced a low-pressure switch. After the maintenance, the mechanic conducted operational checks and performed ground runs; no defects were found. The airplane was returned to service, and the pilot flew the airplane the next day, before the accident flight, without any reported mechanical issues. Postaccident examinations of the cockpit control pedestal and feathering systems did not reveal any anomalies. All propeller condition lever controls were intact and had a full range of motion. Both left and right engine throttle controls were intact and had a full range of motion. Inspections of all accessible wiring and components within the engine nacelles, as well as those contained within the cabin of the aircraft and rigging under the floor panels, revealed no anomalies. Examination of both engines’ propeller governors, fuel control units (FCUs) and beta valves did not reveal any anomalies. These detailed examinations could not determine the reason for the reported propeller feather issue on takeoff.

On December 28, 2021, about 1150 central standard time, a Beech A100 airplane, N93GT, was substantially damaged when it was involved in an accident near West Helena, Arkansas. The pilot and 4 passengers were not injured. The flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91 as a business flight. The airplane had just been in maintenance on the day before the accident to troubleshoot a propeller feather issue. According to a work order, a mechanic found the low-pressure switch on the left engine to be inoperative, replaced the switch, and performed multiple ground runs and system tests. No further defects were found, and the airplane was returned to service. The pilot was briefed on the issue by maintenance. The pilot then flew the airplane solo from Batesville Regional Airport (PMU), Batesville, Mississippi, to Thompson-Robbins Airport (HEE), West Helena, Arkansas, on the morning of December 28, 2021. The pilot reported that there were no mechanical issues during the flight. The pilot arrived at HEE about 1040, and boarded 4 passengers for a flight to Camilla-Mitchell County Airport (CXU), Camilla, Georgia, and taxied the airplane to runway 18 at HEE for takeoff. Immediately after rotation, the pilot noticed that the engines were not producing normal thrust. He also stated that both propellers were going into feather. There was not enough runway remaining to land safely, so the pilot retracted the landing gear and searched for a suitable emergency landing area. The pilot was able to maneuver the airplane back to runway 18. With the combination of low altitude and insufficient thrust, the pilot was not able to slow the descent to the runway. Upon touchdown, the left tire blew, and the airplane skidded onto the grass adjacent to the runway, which resulted in substantial damage to the left wing’s spar. According to the pilot, he was aware of the emergency procedure for an unexpected propeller feathering. He stated that he was able to reduce power as required to keep the engine within the torque limits, but due to low altitude and heavy workload, he was unable to safely remove his hands from the controls to pull the propeller governor idle stop circuit breaker. An examination of the airplane was conducted on February 23, 2023. Examination of the cockpit control pedestal and feathering systems did not reveal any anomalies. All propeller condition lever controls were intact and had a full range of motion. Both left and right engine throttle controls were intact and had a full range of motion. Examination of all accessible wiring and components within the engine nacelles, as well as those contained within the cabin of the aircraft and rigging under the floor panels, revealed no anomalies. Examination of both engines’ propeller governors, FCUs, and beta valves did not reveal any anomalies.