Accident Details
On June 18, 2022, at approximately 0945 central daylight time, a Mooney M20E airplane, registration N5895Q, was involved in an accident near Stillwater, Oklahoma. The airplane sustained substantial damage, but the pilot and passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Engine Power Loss
According to the pilot, about 20 to 25 minutes after departure, while cruising at an altitude of about 4,500 ft mean sea level, the airplane experienced a partial loss of engine power. The engine had been set at 2,400 rpm and 24 inches of manifold pressure, but the power dropped to 2,000 rpm and between 11 and 12 inches of manifold pressure. The pilot manipulated the throttle control, but the engine did not respond. He also moved the fuel selector through all positions while moving the throttle, but the engine still failed to respond.
Forced Landing and Damage
Unable to maintain level flight, the pilot chose to conduct a forced landing on a highway. As the airplane was about to land, the pilot became focused on avoiding a vehicle and failed to extend the landing gear. The airplane touched down "very softly" with the gear retracted. The pilot then turned the airplane slightly to the left to keep the propeller from impacting the vehicle, resulting in the left wing striking a road barrier. This collision caused substantial damage to the wing.
Examination
A postaccident examination of the airplane revealed no anomalies with the engine control system, and throttle control continuity was confirmed from the cockpit to the engine. The engine cowling was removed, and the induction air coupling was found wrapped in gray tape. When the tape was removed, separations were visible on the top and bottom at the flange on the inboard side. Internal examination of the coupling showed the lower portion appeared permanently deformed in a manner consistent with compression.
Maintenance History
The pilot reported the airplane’s tachometer time at the accident was about 4,489 hours. According to maintenance logbooks, the most recent annual inspection was performed on June 11, 2021, at a tachometer time of about 4,429 hours. The same airframe and powerplant mechanic with inspection authorization completed that inspection and the two previous annual inspections on November 11, 2018, and December 7, 2019, at tachometer times of about 4,380 and 4,396 hours, respectively. The maintenance entry from November 11, 2018, noted the installation of a new Brackett induction air filter. No other entries in the logbooks were associated with the induction air filter or coupling. Multiple attempts to contact the mechanic were unsuccessful, so the investigation could not determine when the gray tape was applied to the induction coupling.
According to Title 14 Part 43 Appendix D, during an annual inspection, lines, hoses, and clamps should be checked for leaks, improper condition and looseness, and all systems should be checked for improper installation, poor general condition, defects, and insecure attachment.