What happened
On the morning of May 28, 2009, a Piper PA-28-140, registration OH-PJY, crashed into an open-pit mine near the Kalajoki aerodrome. The pilot, who was conducting a solo test flight to assess weather conditions for a planned afternoon flight with passengers, was killed instantly upon impact. The aircraft caught fire following the collision.
Prior to takeoff, the pilot performed an external inspection and disconnected the wing tie-downs but failed to notice that the tail tie-down was still attached to a 65 kg anchor weight. During taxi and takeoff from runway 23, the weight was dragged behind the aircraft. Witnesses observed the flight appearing unstable, noting a dark object swinging from the tail. As the aircraft approached the aerodrome at an altitude of less than 50 meters, it encountered turbulent air currents rising from the nearby quarry. The aircraft experienced violent rolling and pitching motions before stalling and plunging into the mine.
The investigation
The investigation established that the tail tie-down had been secured the previous evening by a club member to protect the aircraft from forecasted stormy winds. Because the club relied on various members to manage the aircraft on a rotating basis, there was no single person responsible for oversight.
Investigators found that the strong and gusty winds present during taxiing and takeoff masked the vibrations and jerking caused by the trailing weight. The investigation also examined the aerodynamic impact of the weight, noting that the presence of the 65 kg mass shifted the aircraft's center of gravity behind the allowable limit, making the longitudinal stability highly sensitive.
Findings
- The primary cause of the accident was the failure to disconnect the tail tie-down anchor during the pre-flight inspection.
- The trailing weight significantly degraded the aircraft's flight characteristics, specifically increasing interference drag and making the aircraft highly sensitive to pitch control.
- The heavy, gusty winds caused the aircraft to shake while on the ground, which prevented the pilot from detecting the abnormal tugging and movement caused by the attached weight.
- The aircraft's stability was further compromised by the shift in the center of gravity caused by the 65 kg mass.
- Encountering turbulent airflows and vertical currents from the edge of the quarry at a low altitude led to the final loss of control and the subsequent stall.