What happened
On the evening of January 9, 2002, an AS 202-18 A4 Bravo aircraft, registration OH-NTM, crashed on the airfield at Helsinki-Malmi airport immediately following takeoff. The aircraft was being operated by Pilot Factory Oy for a night landing practice session. The pilot, who was a student performing a solo training flight, was the sole occupant of the aircraft.
After receiving taxi instructions, the pilot lined up on runway 27 and received clearance for a touch-and-go maneuver. During the initial climb, at an altitude of approximately 200 to 250 feet, the aircraft experienced a sudden engine malfunction. The pilot broadcast a distress message via radio, reporting the engine failure. Witnesses observed the engine RPM fluctuating before the engine eventually stopped completely. The aircraft's climb leveled off and then transitioned into a shallow glide before banking sharply to the left. As the aircraft descended, the airspeed decreased and the rate of descent increased, resulting in a high-impact collision with the ground.
The investigation
The investigation examined the aircraft's technical condition, the pilot's training, and the sequence of events leading to the crash. Investigators inspected the wreckage and the accident site, and analyzed the engine's fuel system. A significant finding during the technical examination was the presence of greenish oil discovered within the engine's fuel control unit. The investigation also reviewed the pilot's recent flight history, noting that the student had completed several training flights earlier that day and had requested the night flight session to practice landings.
Findings
- The primary cause of the accident was an engine failure during the takeoff phase.
- The engine malfunction was characterized by fluctuating RPMs followed by a total loss of power.
- The pilot attempted to execute a turn back to the field from a low altitude, a maneuver that is rarely successful following an engine failure during takeoff.
- Discrepancies were noted between the flight school's operational checklists and the official aircraft flight manual, specifically regarding the use of the fuel selector valve, which had prevented the establishment of a standardized procedure.
- The presence of unusual oil in the fuel control unit was identified as a technical concern.