Sighting in Bagnères-de-Bigorre, May 22, 2017

At about 9:45 p.m., a witness looking out of their window saw an orange trail in the sky in the direction of Tarbes. They first took it for an aircraft contrail, but its thickness and above all its curved shape puzzled them, and they wondered whether a plane was in trouble. They took a series of photographs and contacted two gendarmerie stations. No other witness came forward.

Analysis of the photographs, together with the oddities the witness had noted (the width of the trail and how long it took to fade), pointed to an aircraft dumping fuel. It also made it possible to work out several scenarios for the aircraft's position and speed. An airliner was ruled out: it would have shown up on public flight-tracking sites, and a fuel dump would have meant a diversion, which would have left a record. A military aircraft, by contrast, would not necessarily appear on public sites. The CNOA radar data covered too short a stretch to be useful and could no longer be obtained after two months. The CNOA could not supply any record of a fuel dump, but the search came too late to be run across every squadron in France, and such an operation is not always logged, since for a military aircraft it is not always critical.

The lack of a record therefore did not invalidate the hypothesis, which was supported by the close match between the testimony, the photograph and the trajectories reconstructed. The account was precise and the photos usable. GEIPAN classified the case as B: a probable kerosene dump by a military aircraft at high altitude, apparently to limit the impact on the environment and the population.