Sighting in Paris, August 21, 2014

A witness was travelling on a passenger flight to Lisbon when, at 12:43, they noticed an object that seemed to be at the same altitude as the aircraft. Through the window, they first took it for a bird or a drone. As it came closer, they saw what looked like a small black box at the front, followed by trails resembling the fins of a Japanese goldfish. The trails, which the witness took to be a propulsion system, were not horizontal but drooped downward. The witness then thought of taking pictures with their mobile phone, and only one photo shows the object. GEIPAN collected this single testimony, along with photos and sketches.

The investigation concluded that the witness most probably saw the contrail of another airliner, which appears in the traffic data and had just crossed the path of the witness's aircraft from left to right, about 900 m lower. The sun was roughly behind the witness and the background was bright, which explains the black colour of the trail, as well as that of a cloud visible in the photo. Reconstructing the relative movements of the two aircraft matches the scene, but with a 52-second offset from the time of the photo. This gap may come from a poorly set phone clock combined with imprecision in the Planefinder data. Any other cause would be very unlikely: it would require a coincidence of perspective within a few tens of seconds, and it would be hard to understand why the witness, already alerted, did not react 52 seconds later when the airliner replayed the same scene. The testimony is highly consistent and the photo could be analysed, so GEIPAN classified the case as A.