According to a government official involved in overseeing airplane safety during the last year, over 75 percent of the voice-recorder tapes taken from small airplanes involved in relatively minor accidents record the whistling of the pilot during the fifteen minutes immediately preceding the accident  Even such minor accidents pose some safety risk
Ttherefore, if passengers hear the pilot start to whistle they should take safety precautions, whether instructed by the pilot to do so or not
provides no information about the percentage of all small airplane flights during which the pilot whistles at some time during that flight