B5/2009L Accident near the extended centerline of Kalajoki aerodrome runway 23 on 28 May, 2009

An accident occurred close to the extended centreline of Kalajoki aerodrome runway 23 at approximately 09:35 on Thursday, 28 May, 2009. On a local flight, the Kalajoki Aviation Club-owned Piper PA-28-140, registration OH-PJY, collided with the ground and was completely destroyed. On 1 June 2009, Accident Investigation Board Finland appointed commission B5/2009L to investigate this incident. Investigator Pekka Alaraudanjoki was named investigator-in-charge, accompanied by investigators Ari Huhtala and Juhani Mäkelä as members of the commission.

The pilot had intended to take two passengers for a flight in the vicinity of Kalajoki during the afternoon of 28 May. However, since the wind was strong and gusty he decided to do a solo flight in the morning so as to test the suitability of the weather for flying with passengers. Prior to the flight during the external inspection, he disconnected the wing tie downs. However, he failed to disconnect the tail tie down. As he taxied, the 65 kg tie down anchor was dragged along behind the aircraft. Judging by the marks the anchor left on the ground, he took off from runway 23 into the headwind. Eyewitnesses described the flight as unstable and detected a dark object dangling from the tail of the aircraft. Prior to the collision with the ground the aircraft was spotted north of the aerodrome, heading towards it at an altitude below 50 m. The aircraft and the anchor were seen to be violently pitching and rolling. There is an open-pit mine on the right side of the extended centreline of runway 23, approximately one and a half kilometres before the threshold. As it was passing over the edge of the quarry at a low altitude, the aircraft was seen to roll to the left followed by a rapid roll to the right, after which it plunged into the mine. The pilot was instantly killed in the crash and the aircraft caught fire after colliding with the ground.

Investigation revealed that in the summertime Kalajoki Aviation Club kept the aircraft at a stand on a grassy area next to the Kalajoki aerodrome apron. The tie down anchors typically remained at the stand throughout the summer, whether they were being used or not. Normally, the aircraft would only be moored at the wings; when winds were strong the tail tie down anchor would also be used. The wind was strong and gusty the day before the accident flight and since the forecast also included strong winds for the day of the flight, a member of the aviation club checked the mooring lines late in the previous evening and also fastened the tail anchor to the tailhook. The club had not assigned anyone to specifically look after the aircraft when it was not being flown. Rather, all (four) persons involved with flight activities took care of the aircraft within the constraints of their own personal schedules. In general, all activities at the club were conducted in accordance with the Aircraft Operating Manual as well as general aviation regulations. The club had not instituted any other dedicated guidelines for its activities.

The accident was caused by the tail tie down anchor which the pilot neither noticed nor disconnected during the external inspection. The anchor degraded the flight characteristics to such an extent that the pilot found it difficult to control the aircraft in the strong and gusty wind. As he entered the final approach at a low altitude, encountering strong wind turbulence coming from the quarry, he finally lost control of the aircraft. As a result, the aircraft stalled and crashed into the open-pit mine.

The strong and gusty wind shook the aircraft while still on the ground, making it difficult for the pilot to detect the tie down anchor was still connected or the shudder and jerk it caused during taxi and takeoff.

The investigation commission issued no safety recommendations.

B5/2009L Report (pdf, 1.15 Mt)