Casualties unknown

1995-08-31: AVIONS PIERRE ROBIN S.A. ROBIN DR 400/140 B (HB-KBD) — Bern Flughafen (LSZB), BE, CH

Bern Flughafen (LSZB), BE, CH

On August 31, 1995, an AVIONS PIERRE ROBIN S.A. ROBIN DR 400/140 B (registration HB-KBD) was involved in an aviation accident near Bern Flughafen (LSZB), BE, CH. Investigators recorded the probable cause as: The accident was the result of a loss of control following an unintentional rearward movement of the unsecured pilot seat during the takeoff phase. This summary draws on records from the Swiss Transportation Safety Investigation Board (STSB / SUST).

Sourcesthe Swiss Transportation Safety Investigation Board (STSB / SUST)Primary reportUpdated 1785639345Data APIEditorial standards

On 31 August 1995, a Robin DR400-140B, HB-KBD, crashed at Bern Airport shortly after takeoff, killing all four occupants. The accident was caused by a loss of control due to the unsecured pilot seat sliding backward.

History of the Flight

On 31 August 1995, at 0959 local time, the pilot, accompanied by three passengers, departed from runway 14 of Bern Airport on a private flight to Sion. Shortly after takeoff, witnesses observed a sudden pitch-up, followed by lateral instability and a left turn that progressively tightened. After completing approximately 270° of turn, the aircraft stalled on the left wing and impacted a sports field in a near-vertical attitude. A fire erupted upon impact.

Injuries to Persons

The pilot and three passengers sustained fatal injuries.

Damage to Aircraft

The aircraft was destroyed by impact and fire.

Other Damage

Grass on the sports field was damaged.

Personnel Information

The pilot, a Swiss citizen born in 1948, held a valid commercial pilot license with ratings for single-engine aircraft up to 2500 kg, VFR and CVFR. His total flying experience was 1094 hours on motorized aircraft, including 24:40 hours on the accident type. His last medical examination on 20 April 1995 found him fit without restrictions. The three passengers had no pilot licenses or experience.

Aircraft Information

The aircraft, a Robin DR400-140B (serial number 1724), was powered by a Textron Lycoming O-320-D2A engine producing 160 HP. It had a fixed tricycle landing gear. The aircraft was certified for VFR day and night operations. Its maximum takeoff mass was 999 kg; at the time of the accident, the mass was approximately 915 kg, within limits. The last 100-hour inspection was on 16 May 1995, and the last 50-hour inspection on 11 July 1995.

Meteorological Information

The weather at the accident site was clear skies, visibility more than 10 km, wind from the southeast at 2–5 knots, temperature 10°C, dew point 6°C, QNH 1021 hPa. The sun azimuth was 114°, elevation 32°.

Wreckage and Impact

The aircraft struck the ground in an almost vertical dive at the western edge of the sports field. It was largely consumed by fire, except for parts of the vertical tail. Examination of flight controls revealed no pre-existing defects. The seat belts were worn and held, though some attachments were torn. Propeller blade deformation indicated the engine was developing full power at impact. The pilot's longitudinally adjustable seat was found unsecured, with its locking pins not engaged in the seat rail holes.

Medical and Pathological Findings

Autopsy of the pilot revealed competing causes of death: brain injury and hemorrhage from chest trauma. The fire occurred post-impact. There were no signs of incapacitating disease, though coronary artery narrowing (up to 70%) was noted; however, vital reactions confirmed heart activity at the time of injury. Toxicology tests were negative for alcohol, drugs, and carbon monoxide. Autopsy of the front-right passenger showed severe injuries, including heart rupture, and hand fractures consistent with possible control input at impact. The two rear passengers died from severe head trauma.

Fire

The aircraft caught fire after impact and burned completely.

Survival Aspects

The accident was not survivable.

Tests and Research

In cooperation with the Federal Office for Civil Aviation, the seat locking mechanism design was examined on other aircraft of the same type, revealing deficiencies that could prevent automatic locking.

Probable cause

The accident was the result of a loss of control following an unintentional rearward movement of the unsecured pilot seat during the takeoff phase.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/1612.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.