NATIONAL TRANSPORTATION SAFETY BOARD
Public Meeting of February 26, 2004
(Information subject to editing)
Report of Aviation Accident
Loss of Pitch Control During Takeoff
Air Midwest Flight 5481, Raytheon (Beechcraft) 1900D, N233YV
Charlotte, North Carolina, January 8, 2003
NTSB/AAR-04/01
This is a
synopsis from the Safety Board’s report and does not include the Board’s
rationale for the conclusions, probable cause, and safety recommendations. Safety Board staff is currently making
final revisions to the report from which the attached conclusions and safety
recommendations have been extracted.
The final report and pertinent safety recommendation letters will be
distributed to recommendation recipients as soon as possible. The attached information is subject to
further review and editing.
On January 8, 2003, about
0847:28 eastern standard time, 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,
Charlotte, North Carolina. The 2
flight crewmembers and 19 passengers aboard the airplane were killed,
1 person on the ground received minor injuries, and the airplane was
destroyed by impact forces and a postcrash fire. Flight 5481 was a regularly scheduled
passenger flight to Greenville-Spartanburg International Airport, Greer, South
Carolina, and was operating under the provisions of 14 Code of Federal Regulations Part 121 on
an instrument flight rules flight plan.
Visual meteorological conditions prevailed at the time of the
accident.
The National Transportation
Safety Board determines that the probable cause of this accident was the
airplane’s loss of pitch control during takeoff. The loss of pitch control resulted from
the incorrect rigging of the elevator control system and the airplane’s aft
center of gravity, which was substantially aft of the certified aft limit. Contributing to the cause of the
accident were Air Midwest’s and the Federal Aviation Administration’s (FAA) lack
of oversight of the work being performed at the Huntington, West Virginia,
maintenance station, the Raytheon Aerospace quality assurance inspector’s
failure to detect the incorrect rigging of the elevator control system, Air
Midwest’s weight and balance program at the time of the accident, and the FAA’s
average weight assumptions in its weight and balance program guidance at the
time of the accident.
The safety
issues in this report focus on maintenance work practices, oversight, and
quality assurance; aircraft weight and balance programs; maintenance training;
FAA oversight; and Beech 1900 cockpit voice recorder problems. Safety recommendations concerning these
issues are addressed to the
FAA.
NTSB supported 47
investigators and staff during the course of this investigation. The core investigative team consisted of
six staff that conducted additional interviews, performed ground tests, visited
manufacturer’s and operator’s facilities, conducted metallurgical examinations
and wrote this report. An estimated
eight man-years or at least 16,000 hours was spent on this investigation. The Public Hearing on Air Midwest flight
5481 was held May 20-21, 2003. It
was the first all electronic public hearing held at the Board. The technical review was held on June
20, 2003. We are bringing the blue
cover report before the Board in just over a year after the
accident.
1. The captain and the first officer were properly certificated and qualified under Federal regulations. No evidence indicated any preexisting medical or behavioral conditions that might have adversely affected their performance during the accident flight. Flight crew fatigue was not a factor in this accident.
2. The accident airplane was properly certified and equipped in accordance with Federal regulations. Except for the elevator control system, no evidence indicated that the airplane was improperly maintained. The recovered components showed no evidence of any preexisting structural, engine, or systems failures.
3. Weather was not a factor in this accident. The air traffic controllers that handled the accident flight were properly trained and provided appropriate air traffic control services. The emergency response for this accident was timely and effective. The accident was not survivable for the airplane occupants because they were subjected to impact forces that exceeded the limits of human tolerance.
4. The accident airplane entered the detail six-maintenance check with an elevator control system that was rigged to achieve full elevator travel in the downward direction.
5. The accident airplane’s elevator control system was incorrectly rigged during the detail six maintenance check, and the incorrect rigging restricted the airplane’s elevator travel to 7º airplane nose down, or about one-half of the downward travel specified by the airplane manufacturer.
6. The changes in the elevator control system resulting from the incorrect rigging were not conspicuous to the flight crew.
7. The Raytheon Aerospace, LLC, quality assurance inspector did not provide adequate on-the-job training and supervision to the Structural Modifications and Repair Technicians mechanic who examined and incorrectly adjusted the elevator control system on the accident airplane.
8. Because the Raytheon Aerospace quality assurance inspector and Structural Modifications and Repair Technicians mechanic did not diligently follow the elevator control system rigging procedure as written, they missed a critical step that would have likely detected the misrig and thus prevented the accident.
9. A complete functional check at the end of maintenance for critical flight systems or their components would help to ensure their safe operation, but no such check is currently required.
10. Flight 5481 had an excessive aft center of gravity, which, combined with the reduced downward elevator travel resulting from the incorrect elevator rigging, rendered the airplane uncontrollable in the pitch axis.
11. Air Midwest’s weight and balance program at the time of the accident was not correct and resulted in substantially inaccurate weight and balance calculations for flight 5481.
12. Air Midwest’s revised weight and balance program is also unacceptable because it may result in an inaccurate calculation of an airplane’s center of gravity position.
13. Air Midwest did not adequately oversee the work performed by Raytheon Aerospace and Structural Modifications and Repair Technicians personnel at its Huntington, West Virginia, maintenance station and did not ensure that the accident airplane was returned to service in an airworthy condition.
14. When an inspector provides on-the-job training for a required inspection item (RII) maintenance task and then inspects that same task, the independent nature of the RII inspection is compromised.
15. Air carriers that use contractors to perform required inspection item maintenance tasks and inspections need to provide substantial and direct oversight during each work shift for this work to ensure that it is being properly conducted.
16. Air Midwest did not have maintenance training policies and procedures in place to ensure that each of its maintenance stations had an effective on-the-job training program.
17. It is important that air carrier on-the-job training programs are developed in accordance with detailed guidance that emphasizes effective training practices.
18. Air Midwest did not ensure that its maintenance training was conducted and documented in accordance with the company’s maintenance training program, which degraded the quality of training and inspection activities at the Huntington, West Virginia, maintenance station.
19. Air Midwest’s Continuing Analysis and Surveillance System program was not being effectively implemented because it did not adequately identify deficiencies in the air carrier’s maintenance program, including some that were found by the Federal Aviation Administration before the flight 5481 accident.
20. Accurate and usable work cards developed jointly by air carriers and aircraft manufacturers would improve the performance of maintenance for critical flight systems.
21. The Federal Aviation Administration’s failure to aggressively pursue the serious deficiencies in Air Midwest’s maintenance training program that were previously and consistently identified permitted the practices that prevailed at the Huntington, West Virginia maintenance station and during the accident airplane’s detail six-maintenance check.
23. Because proper aircraft maintenance is crucial to safety, air carrier maintenance training programs should be subject to the same standard that exists for other air carrier training programs (that is, Federal Aviation Administration approval).
24. The lessons learned by the Federal Aviation Administration through its human factors research program need to be used to develop mandatory programs to prevent human error in aviation maintenance.
25. The use of average weights does not necessarily ensure that an aircraft will be loaded within its weight and center of gravity envelope.
26. The Federal Aviation Administration’s average weight assumptions in Advisory Circular 120-27C, “Aircraft Weight and Balance Control,” were not correct.
27. Periodic sampling of passenger and baggage weights would determine whether air carrier average weight programs are accurately representing passenger and baggage loads.
28. Current safety margins in air carrier average weight and balance programs do not ensure that aircraft will be loaded within their manufacturer-certified and Federal Aviation Administration-approved weight and center of gravity envelope.
29. Technology may enable air carriers to accurately determine weight and effectively control balance while maintaining operational efficiency.
31. Because the cockpit voice recorder (CVR) can be one of the most valuable tools used for accident investigation, reliable daily test procedures are needed to safeguard CVR data.
The National
Transportation Safety Board determines that the probable cause of this accident
was the airplane’s loss of pitch control during takeoff. The loss of pitch control resulted from
the incorrect rigging of the elevator control system compounded by the
airplane’s aft center of gravity, which was substantially aft of the certified
aft limit.
Contributing to the cause of the accident was: (1) Air Midwest’s lack of
oversight of the work being performed at the Huntington, West Virginia,
maintenance station; (2) Air Midwest’s maintenance procedures and documentation;
(3) Air Midwest’s weight and balance program at the time of the accident; (4)
the Raytheon Aerospace quality assurance inspector’s failure to detect the
incorrect rigging of the elevator system; (5) the FAA’s average weight
assumptions in its weight and balance program guidance at the time of the accident; and (6) the
FAA’s lack of oversight of Air Midwest’s maintenance program and its weight and
balance program.
As a result of the investigation of this accident,
the National Transportation Safety Board makes the following
recommendations:
To the Federal Aviation
Administration:
6. Prohibit inspectors from performing required inspection item inspections on any maintenance task for which the inspector provided on-the-job training to the mechanic who accomplished the task. (A-04-XX)
9. Audit training records for personnel who are currently performing maintenance on Air Midwest airplanes to verify that the training was properly accomplished in accordance with the company’s Maintenance Procedures Manual and Maintenance Training Manual. (A-04-XX)
14. Identify those situations that would require the use of actual instead of average weights in weight and balance computations and incorporate this information into Advisory Circular 120-27, “Aircraft Weight and Balance Control.” (A‑04-XX)
19. Conduct or sponsor research to develop systems that are capable of delivering actual aircraft weight and balance data before flight dispatch. These systems should rapidly provide accurate and reliable weight and balance data. (A‑04‑XX)
20. Promote the use of systems that deliver accurate weight and balance data as a preferred alternative to the use of average weight and balance programs. (A‑04-XX)
To the Federal Aviation Administration:
1. Require that all operators of airplanes equipped with a cockpit voice recorder (CVR) test the functionality of the CVR system prior to the first flight of each day, as part of an approved aircraft checklist. This test must be conducted according to procedures provided by the CVR manufacturer and shall include, at a minimum, listening to the recorded signals on each channel to verify that the audio is being recorded properly, is intelligible, and is free from electrical noise or other interference. (A-02-25)
As a result of
the investigation of this accident, the Safety Board issued the following
recommendation on January 2, 2004:
To the Federal Aviation
Administration:
1. Identify all airplanes equipped with unguarded flight crewmember rotary seatbelt buckles and require replacement with guarded buckles that cannot be inadvertently unlatched. (A-03-57)
Safety
Recommendation A-03-31 (previously classified “Open—Response Received”) is
classified “Closed—Superseded” in section 2.5.1.4 of this report.