The National Transportation Safety Board determined today that the probable cause of an airliner crash in Charlotte, North Carolina, last year was the airplane's loss of pitch control during takeoff. The loss of pitch control was the result of incorrect rigging of the elevator control system compounded by the airplane's center of gravity, which was substantially aft of the certified aft limit.
"This accident shows how important it is for everyone involved in the safety chain to do their jobs properly, " said NTSB Chairman Ellen Engleman-Conners. "It is imperative that the recommendations we've issued today be implemented so that tragedies like this not be repeated."
On January 8, 2003, Air Midwest (doing business as US Airways Express) flight 5481, a Raytheon (Beechcraft) 1900D, N233YV, crashed shortly after takeoff from runway 18R at Charlotte-Douglas International Airport. Two crewmembers and 19 passengers aboard the airplane were killed. One person on the ground received minor injuries, and the airplane was destroyed by impact forces and a postcrash fire.
Contributing to the cause of the accident, the Board found, were Air Midwest's and the Federal Aviation Administration's (FAA) lack of oversight of the work being performed at Air Midwest's maintenance facility in Huntington, West Virginia. Board investigators found that the accident airplane entered a maintenance check with an elevator control system that was rigged to achieve full elevator travel in the downward direction. However, the airplane's elevator control system was incorrectly rigged during maintenance, and the incorrect rigging restricted the airplane's downward elevator travel to about one-half of the travel specified by the airplane manufacturer.
Air Midwest contracted with Raytheon Aerospace to provide quality assurance inspectors, among other maintenance personnel, for the Huntington maintenance station. Raytheon Aerospace contracted with Structural Modification and Repair Technicians to supply the mechanic workforce. One of these mechanics examined and incorrectly adjusted the elevator control system on the accident airplane. The Board stated that the failure of the Raytheon Aerospace quality assurance inspector to detect the mechanic's incorrect rigging of the elevator control system also contributed to the cause of the accident.
The Board found that the FAA's failure to aggressively pursue the serious deficiencies in Air Midwest's maintenance training program that were previously and consistently identified permitted the practices at the Huntington maintenance facility during the accident airplane's maintenance check. For example, the Raytheon Aerospace quality assurance inspector did not provide adequate on-the- job training and supervision to the Structural Modifications and Repair Technicians mechanic who performed the maintenance on the accident airplane's elevator control system. Furthermore, the quality assurance inspector and the mechanic did not diligently follow the elevator control system rigging procedure as written. As a result, they did not perform a critical step that would have likely detected the misrig and would thus have prevented the accident, the Board concluded.
The Board also found that Air Midwest's weight and balance program contributed to the cause of the accident. At the time of the accident, the program resulted in substantially inaccurate weight and balance calculations for company airplanes. The Board stated that, although Air Midwest revised its weight and balance program after the accident, the program is unacceptable because it may still result in an inaccurate calculation of an airplane's center of gravity position.
The FAA's weight and balance program guidance at the time of the accident also contributed to the accident, the Board noted, because the assumptions in the guidance were incorrect. If the FAA had performed a survey to determine average passenger and baggage weights at the time, the FAA would have realized that these weights were significantly different from the average weights in its weight and balance program guidance and in Air Midwest's weight and balance program. The Board, therefore, concluded that periodic sampling of passenger and baggage weights would determine whether air carrier average weight programs were accurately representing passenger and baggage loads.
The Board's final report includes 21 safety recommendations directed to the FAA. Among the issues discussed in the recommendations are improved surveillance of air carrier maintenance programs, improved maintenance work card and manual instructions, effective weight and balance procedures, and air carrier accountability for all contract maintenance work performed.
Chairman Engleman-Conners noted that 47 NTSB staff members were assigned to all or part of the Safety Board's investigation of this crash. "We devoted more than 16,000 hours of staff time to this investigation in order to complete it in just over a year. I think this was a model for what I hope will be shorter major investigations in the future when circumstances permit."
A synopsis of the accident investigation report, including the findings, probable cause, and safety recommendations, can be found on the Publications page of the Board's web site, http://www.ntsb.gov. The complete report will be available in about 6 weeks.