[D83] DE WINTZENHEIM (68) VERS COLMAR (68) 21.08.2021

On 21 August 2021 at 15:12, a witness driving from Wintzenheim toward Colmar on the D83 saw an unusual object to the east-northeast. It looked like a long, thin white stick and appeared stationary. He initially considered a glider or an aircraft, but could see neither wings nor a tail fin. He took 2 photographs within 2 seconds before buildings blocked his view. He turned back to find it again, without success. GEIPAN assesses the evidential support as good: only one witness, but a remarkably precise account supported by photographs. Here, the source defines evidential support as the quantity of information considered reliable that has been collected for an account. The investigation considered a stationary airship, perhaps carrying advertising, whose shape and colour would fit; a drone above a nearby stadium or car park; and a very low-flying light aircraft or helicopter (see the investigation report). A plot from the National Air Operations Centre (CNOA) confirms air traffic in the observed area at the time. The identifier F-GSLT corresponds to a Héli-Travaux® helicopter flying at low altitude at 77–99 knots. The witness's initial aircraft or glider interpretation seemed unusual to him solely because no wings or tail fin were visible. GEIPAN suggests that a partial reflection of sunlight from the cockpit or rear of the aircraft could explain the appearance. The Sun was near the southwest, at azimuth 218° from geographic north and elevation about 48°, to the right and slightly behind the witness traveling east-northeast. This geometry favors strong specular reflection from suitably oriented metal surfaces or reflective strips. GEIPAN considers the CNOA reconstruction conclusive: the phenomenon was a small helicopter belonging to a works company. It classifies the case A: observation of a helicopter strongly illuminated by the Sun.