Moving in formation in Seine-et-Marne, France

GEIPAN continues to publish all of its archives on its public website www.geipan.fr. Among its publications are old cases classified at the time (A, B, C, or D) that are now being re-examined, with the sole aim of being more relevant in the conclusions. Thanks to new technical means (software) and the investigation experience acquired over all these recent years, this re-examination sometimes leads to new remarks or even a change in classification. This observation case, previously classified D and named COULOMMIERS (77) 12.05.1992, is part of a set of cases recently re-examined. On May 12, 1992, around 10:30 PM, a witness, from the first floor of his home, observes "a yellow luminous spot" in the sky. Joined by a second witness (T2), they observe the UAP, which seems to lengthen and slowly follows an ascending trajectory. In a final phase, the UAP changes direction, revealing behind it a yellow trail. No noise is heard during the observation. The UAP gradually moves away. These two testimonies are recorded at the gendarmerie, which conducts an investigation (see report). At the beginning of the hearing report, T1 reports two other observations made previously. The UAP observed by the two witnesses resembles a simple aircraft, observed in a first phase from the front, landing lights on, seeming motionless or moving slowly because it was heading toward the witnesses; then in a second and third phase, having made a turn while gaining altitude until reaching an atmospheric layer more conducive to the formation of a condensation trail, and seeming to move quickly, "accelerating suddenly" after its turn, because now observed more from the side (see the investigation report). This condensation trail probably even began to be visible at the end of the first phase, as being very short, but since the witnesses could not distinguish the plane from its trail, they initially took the whole thing as being a single object "lengthening," then, when this trail lengthened further after the turn, they distinguished the two. This plane could have taken off under VFRn flight (night flight) from the Auxerre-Branches airport and headed north, facing the witnesses, before making a turn toward the northeast, toward its final destination. The appearance of the UAP described by the witnesses in phase 1 ("yellow luminous spot" shining with a "very strong brilliance") is entirely compatible with this hypothesis, which they only reject because of the absence of perceived noise. However, at great distance and depending on the wind (carrying or not), the noise of an aircraft can very well not be perceived. In the second phase, the description made by the witnesses ("very long luminous trail of the same color as it") fits perfectly with the observation of a condensation trail produced by this plane, being at that moment at an altitude conducive to the formation of such a trail. Since the observation took place at twilight, we tried to determine whether it was possible that this trail was still lit by the sun, which was already 10° below the horizon at the time of the observation. Unfortunately, too many uncertainties in the existing data and variables sensitive to measurements are present and do not allow a certain conclusion on this point. Consequently, GEIPAN classifies the case as B: probable observation of an aircraft.