4 fatalities

Liaison Flight Crash Near Supt Due to Poor Visibility (E-337)

Supt, FranceFlight

On December 2, 1939, an Amiot 143 (registration E-337) operated by French Air Force - Armée de l'Air was involved in an aviation accident near Supt, France in flight. 4 people were killed. Investigators recorded the probable cause as: Controlled flight into terrain resulting from inadequate altitude management during approach in misty conditions. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 2026-08-04Data APIEditorial standards

A liaison aircraft crashed into a forest near Supt while approaching Pontarlier in misty conditions, resulting in four fatalities and one injury among the five crew members.

What happened

The aircraft departed from Montdidier-Assainvillers Aerodrome, also known as Le Fretoy, on a liaison mission bound for Pontarlier. The flight carried five crew members. During the approach phase to Pontarlier, the crew encountered reduced visibility caused by mist. The aircraft descended too low and subsequently impacted trees in the forest of La Joux, located near Supt. This site is situated approximately 25 km west of Pontarlier Airport. The impact resulted in four fatalities and one injury among the personnel on board.

Findings

The official investigation concluded that the accident was caused by a controlled flight into terrain. The primary contributing factor identified was the crew's failure to maintain adequate altitude while navigating through poor visibility conditions.

Probable cause

Controlled flight into terrain resulting from inadequate altitude management during approach in misty conditions.