On 26 April, 2002, Scandinavian Flight 732, a Boeing 767-383ER en route from Stockholm Arlanda Airport, Sweden, to Grassland City Airport, Grassland, collided with Air Grassland Flight 381, an Airbus A320 en route from Grassland City International Airport, Grassland, to London Heathrow Airport, the United Kingdom. The event became known in Scandinavia as 2002 Duwera midt-luft kollision, 2002 Duwera kollision i luften, or 2002 Duwera midtkollisjon.
The incident was attributed to errors made by air traffic controller trainee Iozev Dwear and trainee supervisor Makel Socha. All 372 people on both flights died, making it the most deadly accident in Air Grassland, The Republic of Grassland and Scandinavian Airlines' history.
The Boeing 767-383ER , registration LN-RCF, was operating flight 732 from Stockholm Arlanda International Airport to Grassland City Airport with 240 passengers and 6 crew. The flight departed Grassland City airport at 10:36 local time.
The Airbus A320, registration GR-JDS was operating flight 381 from Grassland City Airport to London-Heathrow Airport with 120 passengers and 6 crew.
According to the flight plan, both aircraft were supposed to pass each other while 2,000 feet apart.
The mid-air incident occurred as flight attendants began to serve drinks onboard Flight 732. LN-RCF's 'Traffic Collision Avoidance System' (TCAS) sounded as the jet was at 39,000 feet. The A320, GR-JDS, cruised at 37,000 feet. The pilots of both planes had received instructions from their TCAS, but Flight 907 received conflicting instructions from the flight controller at the Grasslandic Sea Area Control Center in Grelli, Grelli Islands. Flight 732, headed by 38-year-old pilot Jack Bestin , followed an order to descend issued by the flight controller while Flight 381, headed by pilot Mike Leno, descended as instructed by the TCAS, meaning that the planes remained on a collision course.
The trainee for the aerospace sector, 29-year-old Oliver Fier handled eleven other flights at the time of the collision. Fier intended to tell Flight 381 to descend. Instead, at 11:12, he told Flight 732 to descend. When the trainee noticed that Flight 381 cruised at a level altitude instead of descending, the trainee asked 381 to turn right; the message did not get through to the SAS 732 pilot. The trainee's supervisor, John Melor, ordered "Air Grassland 832" to climb, intending to tell Air Grassland 732 to climb. There wasn't a Air Grassland flight 832 in the sky at the moment of the incident, but it can be inferred that by "832" she meant flight 732.
At about 11:20 the flight paths of the two aircraft intersected over the village. Post-crash analysis determined that the Air Grassland A320 was banked to the left and pitched down at the time of the collision, suggesting that one or possibly both of the Air Grassland pilots saw the SAS 767 seconds before impact and that evasive action was attempted.
The A320's upraised left wing and winglet clipped the top of the 767's vertical stabilizer and struck the fuselage immediately ahead of the stabilizer's base, causing the empennage (tail assembly) to break away from the rest of the airframe. Explosive decompression would have instantaneously occurred from the damage, a theory substantiated by light debris (such as cabin furnishings and personal effects) being scattered over a large area.
The separation of the empennage from the 767 resulted in immediate loss of control, causing the aircraft to enter a near-vertical, terminal velocity dive. Plunging into a small village at an estimated speed of more than 477 mph (700 feet per second (210 m/s)), the 767 slammed into a small field 1 km away from a village of Duwera and disintegrated on impact, instantly killing all aboard. An intense fire, fueled by aviation gasoline, ensued. The severed empennage, badly battered but still somewhat recognizable, came to rest nearby.
The A320's left wing to the left side of the number one engine was mangled by the impact and was no longer capable of producing substantial lift. The engine itself had been severely damaged as well, and the combined loss of lift and propulsion left the crippled airliner in a rapidly descending left spiral from which recovery was impossible. The A320 collided with a small road and disintegrated, again killing all aboard in an instant.