Hard Landing

My father was, at one time in his life, an aircraft repairman (he was also a renowned conjurer, and later a minister and renowned missionary). He and a colleague were tasked with repairing an aircraft, and they completed the work at the end of the day. Everyone else had gone home, so they decided to take the aircraft for a joy-ride. But between their takeoff and landing, a mist crept over the airfield, and obscured their sight of the ground. They had a hard landing, and damaged the aircraft. Then they spent all night repairing the damage. OBSERVATION: Just as responsible employees would do.