B2/2005L Aircraft accident at Helsinki-Vantaa airport on 31 January 2005

On Monday 31.1.2005, an aircraft accident occurred at around 17:00 co-ordinated universal time (UTC) at Helsinki-Vantaa airport. A Swedish Cessna 208B aircraft registered SE-KYH, owned by Nord-Flyg AB and transporting air freight to Sweden, crashed into the ground within the air-side after takeoff. The pilot suffered minor injuries. The aircraft was completely destroyed. On 2.2.2005, the Accident Investigation Board Finland (AIB) decided to appoint an investigation commission, B 2/2005 L, for this accident. Air accident investigator Hannu Melaranta was named investigator-in-charge with investigators Hannu Vartiainen and Esko Tilli as members of the commission. On 17.3.2005, the AIB augmented the commission by nominating investigators Martti Lantela and Jari Hiltunen as Search and Rescue (SAR) experts.

The aircraft arrived from Sweden on 31.1.2005, landing at Helsinki-Vantaa airport around 02:47. According to standard company policy, Nord-Flyg AB operates with a two person crew. However, on the day in question the co-pilot had taken ill and the flight was flown without a co-pilot. The pilot checked in for duty at the airport at around 14:30 to prepare for the return leg. It had been snowing at the airport until 09:20 and the temperature was hovering at around zero degrees Cel-sius. After having arrived at the airport, the pilot began to brush the accumulated snow and frozen snow melt off the upper surfaces of the aircraft. As per his account, there was a great deal of snow and ice on the aircraft. He did not, however, manage to brush all of the impurities off of the surfaces of the aircraft. The cargo going to Sweden did not arrive in time for him to fly it to Skavs-ta, his primary destination. Therefore, he phoned in a change to the flight plan choosing Örebro instead as his destination. He took off from runway 22L. All went well until he reached the height of 800-1000 ft (250-300 m) and retracted the trailing edge flaps. Immediately after flap retraction, the pilot lost control of the aircraft, which began turning to the right. The pilot attempted to fly the aircraft to the end section of runway 22R to make an emergency landing but the aircraft crashed into the terrain between the runways.

Investigation revealed that the pilot did not succeed in brushing the snow and ice off of the upper surfaces of the wings, fuselage and stabilizers. When the wreckage was examined, it was estima-ted that the coat of snow, frozen slush and ice on the upper surface of the wings and on the sides of the fuselage varied between 0.5-1.5 cm in thickness. As the pilot retracted the flaps from the takeoff setting, the compacted snow and ice on the upper surface of the wing disturbed the lift enough to induce a stall. The aircraft rolled to the right and lost altitude. The pilot was unable to recover and the aircraft hit the ground at a shallow dive angle and was destroyed. At the ime of impact the trailing edge flaps were in the clean configuration. The Emergency Locator Transmitter (ELT) was activated in the crash. An aircraft accident alarm was immediately sounded. A Border Guard helicopter located the wreckage of the plane approximately half an hour after the accident took place.

The primary cause of the accident was that the pilot executed a takeoff with an aircraft whose aerodynamic properties were fundamentally degraded due to the accumulated ice and snow on the upper surface of the wing. During the initial climb and immediately after flap retraction, airflow separated from the surface of the wing and the pilot did not manage to regain control of the airc-raft. The pilot did not recognize the stall and did not act in the manner required to recover from one or, it might be that he had not received sufficient training for such situations.

The investigation commission issued four safety recommendations. The recommendation for the Civil Aviation Administration is that measures be taken to incorporate a condition in the European Joint Aviation Requirements pursuant to which stall recovery techniques during takeoff and during trailing edge flap retraction should be practiced in the flight training syllabi of commercial pilot’s licences and single-engine certifications. The Swedish aviation authority Luftfartsstyrelsen is advised to audit the company’s operational practices and pilot training so as to guarantee the conditions for safe flight operations. The proposal for all entities participating in Search and Rescue (SAR) activities at Helsinki–Vantaa is to consider arranging joint training for everyone. Furthermore, they should establish how all parties can be guaranteed rapid access to the air-side in emergencies.

B2/2005L Report (pdf, 1.43 Mt)