Sighting in Erevan, December 13, 2023

One evening, during a flight from Yerevan to Paris, two pilots noticed unusual lights in the sky through the cockpit windows. Only one of them gave a statement, which was very complete and detailed. The observation began around 19:00 UTC above the western end of Lake Balaton in Hungary and continued until the start of the descent towards Paris, around 20:40 UTC. That is about 1 hour 40 minutes, although the phenomenon was not visible the whole time. The aircraft flew over Hungary, Austria, Germany, Switzerland and then France.

The phenomenon always stayed close to the star Altair, to the north-west (azimuth 310°). It was made up of white spherical lights that appeared and disappeared, with varying intensity. They sometimes flickered, and could stay still or move in a straight line. Towards the end of the observation, they turned red. In total, more than 4 minutes of video were recorded.

GEIPAN examined two explanations: a military air exercise and satellite flashes. Military manoeuvres did take place in the south-west of England at the time, but this explanation was ruled out. The phenomenon stayed fixed relative to Altair, and its height above the horizon decreased at the same rate as the star's because of the Earth's rotation. It also remained near the horizon even though the aircraft covered a long distance, which shows it was very far away. The shift to red was most likely due to atmospheric density, which absorbs the blue part of the spectrum. All this places the phenomenon above the Earth's atmosphere.

The satellite flash explanation was retained. The observation matches other cases reported by pilots and explained as Starlink cluster flares, meaning flashes from Starlink satellites in operational orbit. A check with Stellarium confirmed that the phenomenon's position relative to the Sun, about 45° from it and less than 10° above the horizon, was favourable to such an observation. The case, of low strangeness but good consistency, was classified A. It closely resembles three other cases investigated by GEIPAN, which support a technical investigation note.