SAULCE (LA) (05) 08.12.2019

On 8 December 2019 around 16:30, a witness watched 2 black trails for about 30 minutes. They appeared vertical and moved slowly. He initially thought they were aircraft contrails affected by the light and took several zoomed photographs. The apparent absence of an aircraft in those images and impression of falling made him consider a crashing aircraft, meteorite or rocket debris. Only 1 account was collected. GEIPAN considered his original contrail explanation: a trail aligned with his sightline and seen shortly after sunset. Contrails can look spectacular in particular weather and astronomical conditions, prompting speculation, and can persist long after the aircraft has passed. GEIPAN cites 2 main supporting features. The black but visible colour fits twilight. The terminator is the imaginary boundary between Earth’s illuminated and shadowed portions; after sunset its apparent height depends on elapsed time, affecting how much sunlight reaches a contrail. The photographed shape consists of 2 parallel, kinked lines, deformed by differing winds aloft and converging where the aircraft is located. An aircraft may be invisible because it is no longer sunlit or has travelled much farther on, leaving a persistent trail. Perspective also matters when an aircraft moves along the line of sight towards or away from the horizon. Here, the trail’s downward development suggests an aircraft moving towards the horizon at constant altitude, giving a false impression of a vertical descent. The exact aircraft could not be identified because the sighting time is uncertain. The source preserves conflicting indications: the witness said “around 16:30” and that the Sun was about to set, the photographs are timestamped 18:21, and the reported Stellarium sunset time is 18:54 local. These are retained as stated, alongside the analysis’s shortly-after-sunset hypothesis. Flightradar nevertheless showed several candidates between 16:30 and 19:00 towards the south-west, the viewing direction. GEIPAN classifies the case A: very high probability of condensation trails, with several possible aircraft.