B11/1996L Aircraft Incident at Kajaani Airport, Finland, on 1 October 1996

On Monday September 30, 1996 an aircraft left engine damage took place during flight SWW 2721 from Dalaman, Turkey to Cologne/Bonn, Germany with a Douglas DC-9-83 (MD-83) aircraft, registered TC-INC, owned by Irish Aerospace Finance Ltd and oper-ated by Turkish Intersun Sunways Havacilic A.S. A loud bang was heard in the cockpit from the left engine two to three minutes after reaching the cruising flight level. The engine continued to run but with increased Exhaus Gas Temperature (EGT), high pressure compressor rotation speed (N2) and fuel flow. The aircraft landed in Cologne/Bonn as planned. There were 129 passengers and seven crew members on board.

No qualified trouble shooting was performed in Cologne/Bonn and flight SWW 2722 departed for Kajaani, Finland with seven crew members on board but without passengers as planned. In the beginning of the takeoff the difference between the left and the right engine acceleration rates to 1,4 Engine Pressure Ratio (EPR) had increased significantly compared to the previous takeoff in Dalaman with the left engine being slower. During the flight to Kajaani the left engine surged when thrust was reduced from climb to cruise first at Flight Level (FL) 350 and later on at FL 330.

The serviceability of the left engine was not assured in Kajaani. A total of 137 passen-gers boarded the aircraft and the crew prepared for the flight SWW 2042 to Dalaman. The aircraft taxied out to the runway and the cockpit crew performed the normal procedures prior to takeoff. A loud banging noise was heard in the aircraft and at the terminal building when thrust was increased and the aircraft made a 180 turn into takeoff position. When the throttles were advanced for takeoff, the left engine did not accelerate normally. The left engine EGT was fluctuating with high peaks and the loud ban ing noise was heard again. The cockpit crew waited for approximately 40 s for the left engine to accelerate. When the engine did not accelerate, takeoff was aborted.

The Accident Investigation Board (AIB), Finland was notified of this incident in the morning of October 1, 1996. The Finnish Ministry of Justice appointed on October 3, 1996 an investigation commission in accordance with the Investigation of Accidents Act (373/85) to investigate the chain of events described above, which was suspected having seriously endangered flight safety. Airline pilot (ret.) Mr Lars Westermarck was appointed investigator-in-charge. Chief air accident investigator Mr Seppo Hämäläinen from the AIB, Finland and inspection supervisor (ret.) Mr Pertti Nenonen were appointed members of the commission. The commission consulted airline pilot Mr Timo Uramaa as an expert on the MD-83. Student of technology and psychology Mr Tero Lybeck assisted in writing the report and in the investigation of the human factors aspects of this incident.

Westermarck, Hämäläinen, Nenonen and Uramaa arrived at Kajaani airport on Tuesday October 1, 1996 at 20.00 local time. The cockpit crew was interviewed and the Universal Flight Data Recorder (UFDR) and the Cockpit Voice Recorder (CVR) removed from the aircraft. The data of the recorders was read out by SAS Flight Analysis in Copenhagen, Denmark.

The Directorate General of Civil Aviation (DGCA), Turkey was notified of this incident and the investigation on October 2, 1996. The DGCA, Turkey did not approve the investigation because it did not consider the case a "serious incident". The DGCA, Turkey did not nominate an accredited representative for the investigation according to the International Civil Aviation Organization (ICAO) Annex 13. Intersun Sunways nomi-nated the company operations advisor as the company representative. The investigation was based on Finnish legislation, ICAO Annex 13 and the Council of the European Union directive 94/56/EC.

Intersun Sunways went into bankruptcy and ceased operations in October 1997. The commission sent the draft of this incident report to the DGCA, Turkey and Flugunfal-luntersuchungsstelle beim Luftfahrt-Bundesamt (Accidents Investigation Bureau at the LBA, Germany) for comments according to ICAO Annex 13 on December 29, 1997. The German aviation authorities did not have any comments on the draft. No reply was received from the DWA, Turkey. The investigation was completed on March 26, 1998.

B11/1996L Report (pdf, 0.41 Mt)