Accident Overview
On 5 July 2006, at approximately 15:17 local time, a Bücker 131 Jungmann aircraft, registered as HB-UUT, was involved in an accident at Granges Airport (LSZG) in Switzerland. The pilot, who was also the owner and operator, sustained serious injuries, and the aircraft was severely damaged.
Sequence of Events
The aircraft had undergone extensive overhaul work on its airframe. Following completion, the pilot conducted four technical flights from Langenthal/Bleienbach (LSPL) airfield, where the final assembly had taken place. On the afternoon of the accident, the pilot decided to ferry the aircraft to Granges Airport.
At 14:55 LT, the pilot departed from Langenthal/Bleienbach. At 15:08 LT, he contacted Granges air traffic control (ATC) to request approach via entry points GOLF and ECHO, indicating his intention to land on grass runway 07L. ATC cleared him to proceed via GOLF ECHO to join a right-hand downwind leg for runway 07L. The pilot integrated into the traffic pattern and appeared to approach normally. During the latter part of the final approach, the aircraft descended below its initial glide path and struck a candelabra located approximately 235 meters from the threshold of runway 07L.
Investigation Findings
The official investigation by the Swiss Bureau d’enquête sur les accidents d’aviation (BEAA) concluded that the accident was caused by a collision with an obstacle following a final approach conducted at too low a height. Two factors were identified that may have played a role in the accident: the pilot's visual acuity at the time of the accident, and the onset of engine seizure.
Technical examination of the aircraft revealed no pre-existing faults that would have directly caused the low approach. The engine showed signs of beginning seizure, but the investigation did not establish a direct causal link to the flight path deviation. The pilot's medical records indicated a possible issue with visual acuity, though its precise influence on the accident sequence could not be definitively determined.
Causes
The BEAA report stated: "The accident is due to a collision with an obstacle following a final approach carried out at too low a height." This was the direct cause. Contributing factors included the pilot's visual acuity and the beginning of engine seizure.