Gulfstream G III Water Impact at Lac du Bourget

Accident Overview and Aircraft Details On 6 February 1998, a Gulfstream G III registered VP-BLN collided with the surface of Lac du Bourget in France. The aircraft was operating a private flight from Geneva to Chambéry under an instrument flight rules (IFR) flight plan. The operator was private, with technical management provided by Jet Aviation Business Jets AG in Zurich, Switzerland. The flight crew consisted of three people, and there were two passengers on board. The accident resulted in one injured occupant and the destruction of the aircraft. ## Flight Progression and Approach The aircraft departed Geneva at 11:20 UTC. During the approach to Chambéry runway 18, the pilot intercepted the localizer for an ILS approach. At 11:31 UTC, the aircraft was cleared to descend to 6,500 feet and transferred to Chambéry approach control. The controller confirmed radar contact and issued the ILS 18 approach clearance with meteorological information. At 11:37 UTC, the pilot reported at 4 nautical miles from the DME and was cleared to land. The aircraft then experienced a higher vertical speed and passed below the normal approach path, striking the water surface approximately 0.6 nautical miles from the runway threshold. ## Crew Experience and Meteorological Conditions The captain was 60 years old with 9,173 total flight hours, including 2,863 on type. The first officer was 44 years old with 2,841 total flight hours, including 415 on type. Meteorological conditions at Chambéry included low clouds and fog during the morning that cleared between 10:00 and 11:00 UTC. At 11:00 UTC, visibility was 2,500 meters with a clear sky. The sun was positioned at an azimuth of 3° east of south and an elevation of 29° above the horizon. ## Rescue and Wreckage Examination A fisherman in the area provided the initial alert using a mobile phone. The occupants evacuated the sinking aircraft quickly, using seat cushions as flotation devices because they did not have time to put on life jackets. Another fisherman recovered them and transported them to a nearby port. The occupants were hypothermic and received medical care; the flight attendant suffered a left arm fracture. The tail section separated from the aircraft upon impact. The CVR support was recovered on the day of the accident, but the recorder itself was not found despite search efforts. Most of the wreckage was recovered between 19 and 21 February 1998, with the tail section recovered on 5 June 1998. ## Contributing Factors The captain had decided to descend below the glide path to execute a flatter approach and reduce braking on the runway. During this descent, the captain was blinded by the sun and lost sight of the runway. The crew did not report any mechanical, instrument, or control problems. The aircraft's operations manual required a go-around if visual contact was lost beyond minimums, but the captain did not consider a missed approach procedure. Mist over the lake reduced visibility and contrast, making it difficult for the crew to estimate altitude visually.