Someone in the military who spends 12-15 hours a day fixing the pieces of junk he or she is expected to keep in top shape for the snooty pilots to fly, while getting paid the same as the guy sitting in the office across the flightline who goes home every day at 4, whether or not his work is done. Crew chiefs possess a finely tuned sense of smartassedness, several bags of scrounge and the unwillingness to put up with stupid people. They are what keeps the aircraft in the air and the bars around the base in business.
"We need another crew chief in on this engine change. You've only been here 9 hours, get to work."