What happened
The aircraft was operating under visual flight rules during daylight hours when the pilot experienced a sudden loss of engine power while in cruise flight. With no immediate airfield available, the pilot maneuvered the aircraft toward Interstate Highway I-85 to execute an emergency landing on the roadway. The attempt ended in a crash when the aircraft struck a support column for an overpass at an altitude of 15 feet above ground level.
The investigation
Records revealed that the engine had undergone an overhaul just 51 hours prior to the accident. Although the overhaul documentation indicated that the magneto had been repaired, and annual inspection records showed compliance with Airworthiness Directive 78-09-07 regarding the magneto, post-crash physical evidence contradicted these claims. Investigators found that neither the carburetor nor the magneto had actually been overhauled.
Further examination of the mechanic involved uncovered a lengthy history of FAA violations for improper repairs. Post-crash testing of the engine components confirmed significant mechanical failures. The left magneto was observed firing intermittently, and the carburetor throttle valve seals were leaking, which induced an excessively lean fuel mixture. Additionally, the carburetor accelerator pump was found to be weak. During a post-crash engine run, the throttle jammed, causing the engine to hesitate, confirming the mechanical deficiencies that led to the power loss.
Findings
The primary contributing factor was the inadequate overhaul of the aircraft engine. The mechanic failed to perform the necessary repairs on the carburetor and magneto despite documentation suggesting otherwise. This lack of proper maintenance resulted in critical component failures, including a leaking throttle valve seal and an intermittent magneto, which directly caused the loss of power during the critical phase of flight.
Safety message
This incident highlights the critical importance of verifying that all required maintenance actions, particularly those mandated by airworthiness directives, are actually performed. Pilots and operators must ensure that mechanics have a clean compliance history and that post-maintenance testing confirms engine reliability before flight.