What happened
On October 9, 1998, at 16:35, a Piper PA-28-140 Mod., registration OH-PCQ, experienced a failed takeoff from runway 18 at Helsinki-Malmi Airport. The aircraft, operated by BF-Lento Oy, was carrying a pilot and three passengers on a private flight.
During the takeoff roll, the aircraft failed to accelerate sufficiently, and the pilot rotated at a high angle of attack. Witnesses and air traffic controllers observed the aircraft flying at a very low altitude, between 10 and 20 meters, with a heavy, labored climb. The pilot experienced stall vibrations and attempted to increase speed by pushing the control column forward, but was forced to pull back again to avoid obstacles.
As the aircraft approached buildings near the Lahdentie junction, the pilot initiated a right turn. During this maneuver, the aircraft stalled and struck trees at an altitude of approximately 16.5 meters. The impact caused the right wing to separate from the fuselage. The aircraft then struck the ground nose-first, flipped onto its back, and came to rest upside down in a ditch. The pilot and one passenger sustained minor injuries, while the two passengers in the rear seats were uninjured.
The investigation
The Finnish Safety Investigation Authority (OTKES) examined the wreckage at Helsinki-Vantaa Airport. Investigators analyzed the engine, propeller, and airframe components. The investigation confirmed that the Lycoming O-320-D2C engine and propeller were in good working condition prior to the impact. While some spark plugs showed lead deposits, they were functional. The stall warning system, which uses a microswitch on the wing leading edge, was found to be operational, though the warning light was lost during the crash.
Investigators also performed a weight and balance reconstruction. It was determined that the aircraft's takeoff mass was 1127 kg, which exceeded the maximum allowable takeoff mass of 997 kg by 130 kg. This represented a 13% overload.
Findings
- The aircraft was overweight by 130 kg at the time of takeoff.
- The pilot failed to perform weight and balance calculations or verify the aircraft's loading before flight.
- The pilot rotated the aircraft at a speed appropriate for a lighter load, resulting in an excessively high angle of attack for the actual mass.
- The high angle of attack created significant drag, preventing the aircraft from accelerating sufficiently.
- The aircraft entered a stall during the climb, leading to the loss of control and subsequent impact with trees.