LONGUEVILLE (77) 05.03.2015

On 5 March 2015 at 07:13, a witness at Longueville station (77) was intrigued by an aircraft contrail's pronounced zigzag shape. GEIPAN agreed that it was unusual and submitted the photograph to Météo-France experts. They identified a contrail deformed after formation by turbulence where it had formed. Their explanation notes that highly turbulent areas can exist in clear skies, termed clear-air turbulence. Pilots regard these areas as hazardous because they are difficult to predict, invisible to radar and subject to violent conditions that require crews to change flight levels for passenger comfort. The experts said a photograph with curves this pronounced was a first for them. This rare case is classified A: a contrail from the Airbus A319 on Air France flight AF7614, Marseille–Lille, strongly distorted by atmospheric turbulence; see the FlightRadar map at 07:13 local time. Attachments include FlightRadar data and Météociel ground weather records at Melun.