GEIPAN Case 2010-01-02498 — TAVERNY (95) 04.01.2010

Brief

On 4 January 2010 at approximately 19h45, a 52-year-old aviation enthusiast walking his dog in a wooded park in Taverny observed a large dark triangular form traveling east to west — counter to normal CDG approach traffic — at an estimated 2,000–3,000 feet altitude, carrying three dim yellow-orange circular lights at its vertices and making no audible sound. GEIPAN opened an initial dossier in December 2012 and conducted a field investigation in February 2013, including GPS-anchored site reconstruction and 3D trajectory simulation. The investigator found the object's trajectory inconsistent with any known CDG departure route and mathematically incompatible with a conventional aircraft given the 45-second observation window and the absence of noise. With no photo or video and a single witness, GEIPAN classified the case D1 — unexplained, medium evidentiary consistency.

Metadata

Agency

GEIPAN / CNES

Release

2007-03-22

Type

PDF • .pdf

Length

25 pages

Classification

UNCLASSIFIED

Programs

GEIPAN, Case 2010-01-02498

Tags

triangular, dark-mass, silent, amber-circular-lights, France, 2010, D1-unexplained, single-witness, counter-traffic-heading, Taverny, Val-d'Oise

Key points

• The witness is a self-described aviation enthusiast who had just watched a fully illuminated A330 pass at ~1,500 feet; he compared the UAP directly against it and ruled out any aircraft in current service.p.2
• The object flew east to west at an estimated 200–250 knots and 2,000–3,000 feet — the opposite direction of CDG approach traffic — with no perceptible noise in a relatively quiet urban environment.p.2
• Three dim yellow-orange circular lights were positioned at each vertex of the triangular form; the leading edge appeared to reflect ambient city light, making a solid dark triangular mass distinguishable against the night sky.p.17
• Trajectory simulation showed the object's path matches neither CDG departure route EVX3A3D nor EVX3Z; a constant-altitude, constant-speed model is mathematically inconsistent with the 45-second observation duration.p.12
• At 250 knots, the object would need to be below 600 meters to fit the 45-second window — yet at that altitude with the required acceleration it should have been audibly loud, contradicting the silence reported.p.12
• The drone or scale-model hypothesis — a 2.5m object at ~150m altitude traveling 35–150 km/h on a silent electric motor — is geometrically consistent with all observed parameters but was not retained for lack of corroborating evidence.p.15
• Meteorological data show contradictory cloud cover: 8/8 at 19h00 and 21h00 but only 1/8 at 20h00 at Le Bourget, suggesting the observation may have occurred during a brief clear interval.p.9
• GEIPAN classified the case D1 — strange, medium-consistency, unexplained — citing the witness's credibility alongside the absence of any photo, video, or second witness.p.15

Verbatim

• Je suis fana d'aviation et je peux confirmer que cet engin ne ressemble à aucun avion en service actuellement malgré sa forme delta.

  p.2

• mon visuel a duré entre 10 et 15 secondes

  p.2

• Ciel bien sombre, ciel bleu nuit, on voyait toutes les étoiles

  p.16

• Trois lumières jaune/orangé très pale, on dirait un peu comme un éclairage de rue, ces réverbères qui sont ronds, et qui sont avec une lampe halogène à l'intérieur, qu'on vient d'allumer, quand la lumière n'a pas encore sa puissance max.

  p.17

• C'est là que j'ai réalisé que c'était quelque chose de solide et la derrière cette lueur qui matérialise le bord d'attaque de l'aile, on distingue (je ne dirais pas on voit) une masse sombre.

  p.17

• Le témoignage serait compatible avec un modèle réduit ou drone de taille de 2.5m volant à 150m d'altitude à environ 35-150km/h en dessous du cône radar du contrôle aérien (CDG) ; il paraît toutefois très peu probable que ce type d'engin vole en milieu urbain, de nuit, un soir d'hiver ; cette hypothèse, bien que pouvant être conforme à l'observation, n'a pas été retenue faute d'autres éléments probants.

  p.15

• Le GEIPAN classe ce cas étrange et moyennement consistant en catégorie D1, comme phénomène inexpliqué.

  p.15

Most interesting

• The witness revised his observation duration from 10–15 seconds in his January 2010 email to 30–45 seconds by the 2013 field interview — a discrepancy the investigator treated as analytically significant, since it changes the implied angular velocity by a factor of roughly three.
• The investigator produced 3D real-time-rendered simulation videos of competing trajectory hypotheses, including a dedicated low-altitude track modeling a small object at 150m.
• Astronomical calculations confirmed the moon was 23 degrees below the horizon and astronomical twilight had ended 43 minutes before the sighting, placing the sky at intrinsic maximum darkness — consistent with the witness seeing a dark solid form silhouetted against it.
• The Taverny military air base sits 2.5km northeast of the observation point, a proximity noted in the geographic context but not developed as a hypothesis in the report.
• The investigator's silence analysis concluded that a temperature inversion — normally invoked to explain inaudible aircraft — could not have applied here, because the object was at approximately 38 degrees above the horizon at closest approach, far too high for sound to be ducted back skyward.
• GEIPAN's D1 classification is the agency's highest-anomaly designation, indicating a case judged both strange and insufficiently explained by any identified natural or man-made phenomenon.