Sighting in Pirmil, February 2, 2013

Several witnesses saw a number of motionless trails in a cloudy sky, which eventually vanished one after another. A child took photographs with a mobile phone. The accounts were gathered through a questionnaire and then through a gendarmerie report.

The investigation found that the photograph, taken at 1/125 s and very sharp, clearly shows aircraft contrails. A dry north wind (65% humidity according to Météociel) kept the contrails short. Sunset was at 18:01 in Le Mans, so the contrails were still in full sunlight while the blue of the sky was starting to darken. This strong contrast made them look like flames. Once the Earth's shadow reached them, they were no longer lit and became invisible, since they were much less bright than the blue sky. The case was classified A: observation of aircraft contrails.