The most common cause of an aviation accident is pilot error, accounting for more than half of the total aviation accidents. Negligence is another common cause, including negligence of Flight Service Station employees, negligence of the ATC (Air Traffic Control), negligence in maintenance and repairs, and negligence in a third party’s selection of a carrier. Other causes include faulty equipment, mechanical failure, manufacturing defects, flaws in structure or design, failure to fuel the aircraft, violations of FAA (Federal Aviation Administration) regulations, dangerous weather, and sabotage. In some cases, however, the cause of an aviation accident remains undetermined.