Both pilots of an Air Comet flight from Lima, Peru, to Lisbon, Portugal, sent a written report on the bright flash they said they saw to Air France, Airbus and the Spanish civil aviation authority, the airline told CNN.

"Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds," the captain wrote.

http://edition.cnn.com/2009/WORLD/americas/06/04/plane.crash

I think you were voted down unfairly. We don't know what happened, but whatever it was, it was instantaneous and caused a bright flash.