My father flew intercept on the north coast of scotland using the real RAF (BAC) Lightnings many years ago. They had a small blackboard in the officers mess without a title. No one was ever told what it was for.
Later he told me it was a count of the number of windows they broke when taking off with the afterburners engaged whilst they were still on the ground during acceleration. The pressure wave would go across the airfield and hit the officers quarters taking out the windows. They had a deal with the repair team to register when they got cracked. The highest score every month had to buy the beers in the bar as a "penalty".
