ERA23FA087 · Mooney M20B

The airplane was on an instrument flight rules flight and in cruise flight at 6,000 ft mean sea level (msl) when the pilot declared “mayday” and reported to air traffic control that the airplane’s engine was running rough. The controller subsequently provided a heading toward the closest airport about 11 nautical miles (nm) away, and upon turning left toward the airport, the pilot announced that the engine had regained power. The pilot elected to continue with the diversion and indicated that he was in instrument meteorological conditions (IMC). The controller continued to provide course guidance and advised the pilot of the weather conditions at the airport, which included an overcast ceiling at 800 ft above ground level. About four minutes after reporting that engine power had been restored, the pilot reported to the controller that he was, “engine out.” Radar contact was lost, and the airplane impacted trees and terrain about 5 nm from the diversion airport. Postaccident examination of the airframe and engine revealed no evidence of preimpact mechanical failures or malfunctions that would have precluded normal operation. The wing fuel tank bladders appeared intact. While there was evidence of fuel leakage from the left wing fuel vent, the right wing remained clean with no evidence of fuel leakage or fuel blighting in the area surrounding the wing. About 18 gallons of fuel was drained from the left fuel tank, while the right tank was found empty. No fuel was found in the fuel hoses and fuel system components. The fuel selector was found positioned to the right wing tank. The airplane was fueled with 22.2 gallons of fuel the day before the flight. The pilot’s phone contained a picture of a fuel receipt for about 38 gallons from the morning of the accident; however, the airplane registration number on this receipt did not match the accident airplane, and this purchase could not be definitively correlated to the accident airplane. Therefore, the total amount of fuel onboard the airplane at the time of departure on the accident flight could not be determined. Based on fuel consumption rates published in the pilot’s operating handbook, the airplane likely consumed about 10.15 gallons of fuel between engine start to the pilot’s first mayday call. If the airplane was fueled to capacity before takeoff, and the pilot had operated exclusively from the right fuel tank during the accident flight, about 17.25 gallons of fuel should have remained in the right tank at the time of the loss of engine power. That the right fuel tank was intact and empty at the accident site suggests the airplane was not fully fueled at the time of departure. A witness recalled the pilot stating before the accident flight that he hoped the airplane was already fueled so that he could get started on his pre-flight checks, indicating that he may have been in a rush to depart. The witness stated that the employee at the airport told him that the airplane was “fueled and ready.” The extent of the pilot’s preflight inspection could not be determined based on the available information. The pilot had flown the accident airplane make and model for the first time the day before the accident flight, for about one hour. The pilot had received about one hour of ground instruction from the owner before the flight, but did not receive any flight training in the accident airplane. Although the pilot’s logbook indicated that he had 18 total hours of experience in actual instrument meteorological conditions (IMC), the date of the last entry was 100 days before the accident flight, and the pilot’s instrument currency and proficiency could not be determined. The pilot sent a text message to a friend after the flight that occurred the day before the accident asking if he needed to switch fuel tanks during flight, indicating that the pilot lacked basic knowledge of the airplane’s fuel system. Additional text messages between the pilot and another friend indicated that the airplane’s autopilot was inoperative. Based on all available information, the circumstances of the accident are consistent with a total loss of engine power due to fuel starvation. Hand-flying the airplane without the aid of a functional autopilot in IMC would have significantly increased the pilot’s workload, particularly while troubleshooting a developing engine issue in an airplane in which he was unfamiliar. This task saturation may have resulted in the pilot forgetting to switch fuel tanks prior to and following the initial engine roughness. Additionally, the low cloud ceiling in the area of the accident site would have left the pilot with little time to locate a suitable landing area for a forced landing.

Verbatim NTSB analysis and probable cause from the NTSB dataset