2 fatalities

Ambulance Flight from Frankfurt to Genoa Crashes on Mt Le Grammont (OY-DZI)

Mt Le Grammont, SwitzerlandFlight

On October 5, 1956, an Avro 652 Anson (registration OY-DZI) operated by Zonen Aviation - Zone-Redningskorpset Flyve-Tjenesten was involved in an aviation accident near Mt Le Grammont, Switzerland in flight. 2 people were killed. Investigators recorded the probable cause as: The exact cause of the accident could not be determined with certainty. However, weather conditions were considered as poor with icing conditions and the assumption that the accident was the result of a navigation error on part of the crew was not ruled out. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 2 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 2026-06-12Data APIEditorial standards

An ambulance flight from Frankfurt to Genoa struck the northeast face of Mt Le Grammont on approach. Both crew members were killed. Poor weather and possible navigation error are cited.

Accident Overview

An ambulance flight from Frankfurt to Genoa to pick up a patient struck the northeast face of Mt Le Grammont (2,172 meters), located six kilometers northwest of Vouvry. The wreckage was found less than ten meters below the summit. Both crew members, Captain Johann-Christian Jessen (pilot) and Niels-Michael Seierde (radio operator), were killed.

Flight Sequence

After passing over Bern, the crew was authorized to descend to 6,000 feet. While passing over the Lake of Geneva, weather conditions worsened. At an altitude of about 5,600 feet, the airplane went through clouds and the pilot made a left turn of 20° for unknown reasons. The airplane then struck the mountain.

Weather Conditions

Weather conditions at the time were described as poor, with icing conditions present.

Investigation Findings

The exact cause of the accident could not be determined with certainty. However, the investigation noted poor weather and icing conditions, and the possibility that the accident resulted from a navigation error on the part of the crew was not ruled out.

Probable cause

The exact cause of the accident could not be determined with certainty. However, weather conditions were considered as poor with icing conditions and the assumption that the accident was the result of a navigation error on part of the crew was not ruled out.