EMERAINVILLE (77) 04.08.2017

On 4 August 2017 between 13:55 and 14:10, a witness noticed an object at what he took to be airliner cruising altitude. Through binoculars he saw an apparently stationary upright cylinder, its top third red-orange and lower two thirds white. A large cloud from the southwest hid it. Two aircraft passed almost directly above the observation area, one west to east and the other southeast to northwest. After the cloud dispersed, the object was gone. He considered a drone despite its high altitude. No other account was collected. GEIPAN locates the perceived strangeness in the apparent immobility, shape and disappearance. Immobility is difficult to judge: although the witness said the cloud covered the UAP, relative movement could partly have been the UAP approaching the cloud. An airliner often appears as a wingless cylinder or cigar. Rounded fuselage or nose surfaces can reflect sunlight fairly continuously, while much stronger wing reflections are fleeting and effectively all-or-nothing. Apparent verticality is subjective: GEIPAN explains that a fuselage appears upright if the aircraft travels in a plane containing the line of sight, horizontal if that plane is transverse. A high aircraft without a contrail may be visible briefly through sunlight reflection, then disappear as reflection geometry changes. Once invisible to the naked eye, it is impossible to relocate it with binoculars. The witness was in an area with heavy aircraft traffic at many altitudes, at least at that time of day. Previous observations of that traffic had already produced strong strangeness and a GEIPAN report, EMERAINVILLE (77) 05.06.2017. GEIPAN considers the aviation-context analysis sufficient to establish that nothing inherently strange is described. Given the very high aircraft probability, it devoted no additional resources to identifying the particular aircraft. Classification A: aircraft.