/
/

Air traffic accident at Gottröra, Sweden December 27, 1991 – KAMEDO-report 63

The Kamedo-reports are published by the Swedish Disaster Medicine Study Organisation (Kamedo), at the National Board of Health and Welfare. Observers study the medical, psychological, organisational and social aspects of disasters. The results, with a focus on experiences gained, are presented in the reports

This report is entirely in Swedish. Only summary in English.

Summary

On December 26, 1991, at 22.09 hrs, a DC 9-81 arriving from Zürich landed at Stockholm-Arlanda airport. After landing approx. 2,550 kg fuel remained in each wing tank. The aircraft was parked outdoors overnight. Prior to take off next morning it was de-iced.

After start 08.47 hrs, in connection with lift-off, an abnormal noise was heard and after approx. 25 seconds flight the right engine started to surge. The captain throttled back on that engine somewhat, but without the surging ceasing. Fifty one seconds after the surges had started the engine stopped delivering thrust. Also the left engine had somewhat later started to surge and lost thrust two seconds after the right engine had failed.

The crew prepared for an emergency landing. When out of the cloud, at a height of 290 metres, the captain elected to try and land in a field in roughly the direction of flight. During the approach the aircraft collided with trees. The major part of the right wing was tom off. The tail of the aircraft struck the ground first. After impact the aircraft slid along the ground for approx. 110 metres before stopping. The fuselage had been broken into three pieces on impact and during the subsequent braking on the ground. The external air temperature was 0°C and on the ground there was a light snow coverage.

The crew and all 123 passengers had survived the crash. All but four of them managed to make their own way out of the aircraft under the guidance of the cabin crew, in about half of the cases through the openings caused by the breaking up of the fuselage. No panic broke out. One passenger had incurred disabling vertebral fractures. Another one was caught fast and could not be helped out until rescue forces arrived.

The injuries were situated as follows:
• Head and face 7
• Unconsciousness 3
• Shoulder and arm 7
• Thorax 4
• Abdomen 0
• Back 9
• Pelvis 0
• Feet and leg 3
Most of those injured, and those with the most serious injuries, had been sitting in the forward part of the aircraft, with a concentration to the right side. Here there were eight of totally nine cases of back injury and five of totally seven shoulder and arm injuries. Another concentration of injuries was among those sitting near the rear fuselage break.

Immediately after the crash the SOS emergency centre in Stockholm (SOS-A) began to alert ambulances to a predetermined break point and some fifteen minutes later eleven ambulances had been alerted. The only ambulance helicopters on standby, a police ambulance helicopter based at Barkarby close to Stockholm and a helicopter from the Swedish Air Force based at Visby airport some 400 km away, were alerted by the Aeronautical Rescue Co-ordination Centre (ARCC) and airborne short after the alert. In addition, another police helicopter with a pilot and a mechanic on board and other helicopter crews not on standby at military bases were contacted to take part in the rescue operation.

The police ambulance helicopter arrived at 09.22 hrs at the site of accident and its crew reported some minutes later that seven people were seriously injured and seven slightly injured. Three of them were transported by the police helicopters to the Academic Hospital of Uppsala and one to Danderyd's Hospital in Stockholm. The others, and passengers with less serious injuries, were taken care of by medical teams and transported by road ambulances and busses.

Hospital (number sent, number received)
The Academic Hospital of Uppsala 3, 3
Danderyd's Hospital 8, 0
Karolinska Hospital 39, 6
Löwenströmska Hospital 5, 3
Norrtälje Hospital 3, 0
Totally 58, 12

The first rescue vehicles and road ambulances arrived at the disaster area some 35 minutes after the crash and within one hour's time medical teams from the hospitals of Danderyd, Karolinska and Huddinge had arrived.

The break point as well as the site of disaster, were not satisfactory as regards radio communication. The staff medical officer at the SOS emergency centre in Stockholm was unable to co-ordinate the transportation of patients to the different hospitals. The doctor in command at the site of disaster succeeded in keeping radio contact with the Karolinska Hospital and the greatest number of patients were transported to this hospital.

As the road between the break point and the accident site was narrow, partly blocked by cars and also very slippery and had to be sanded it took several hours before patients with minor injuries and without injuries could be evacuated by busses.

At hospital, there were no medical or capacity problems except that many patients had to wait long at the x-ray department of Karolinska hospital as many fractures were suspected. The number and severity of the injuries was as follows:

Hospital, received (crew, passengers) 1, 11
Outpatient's care 2, 13
Slight injury or wound 0, 60
Uninjured 3, 39
Totally 6, 123

The Board of Accident Investigation concluded that:
• The accident was caused by inadequate instructions and routines to ensure that clear ice was removed from the wings of the aircraft prior to takeoff. Through this, the aircraft took off with clear ice on its wings. In connection with lift-off clear ice came loose and was ingested by the engines. The ice caused damage to the fan stages of the engines which led to engine surging. The surges destroyed the engines.
• Contributory causes were:
- The pilots were not trained to identify and correct engine surges.
- ATR - which was unknown within SAS - was activated and increased engine throttles within the pilots' knowledge.

Read the full Summary