Accident Prevention May 2004
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FLIGHT SAFETY FOUNDATION Accident Prevention Vol. 61 No. 5 For Everyone Concerned With the Safety of Flight May 2004 Misrigged Elevator and Aft Loading Cause Loss of Control of Raytheon Beech 1900D Limited nose-down elevator travel and an excessive aft center of gravity rendered the twin-turboprop airplane uncontrollable in pitch on takeoff from Charlotte, North Carolina, U.S. The accident report cited incorrect rigging of the elevator-control system and defi ciencies in maintenance oversight and in calculation of passenger weights and baggage weights. FSF Editorial Staff About 0847 local time on Jan. 8, 2003, a Raytheon • “Air Midwest’s weight-and-balance program at Beech 1900D being operated by Air Midwest as the time of the accident; Flight 5481 struck a maintenance hangar and terrain during takeoff in daylight visual meteorological • “The Raytheon Aerospace quality-assurance conditions from Charlotte–Douglas International inspector’s failure to detect the incorrect rigging Airport in Charlotte, North Carolina, U.S. The 21 of the elevator-control system [Raytheon occupants were killed, and one person on the ground Aerospace was a maintenance contractor for received minor injuries. the airline]; The U.S. National Transportation Safety Board • “The [U.S.] Federal Aviation Administration’s (NTSB) said, in its fi nal report, that the probable [FAA’s] average weight assumptions in its cause of the accident was “the airplane’s loss of weight-and-balance program guidance at the pitch control during takeoff [that] resulted from the time of the accident; and, incorrect rigging of the elevator-control system [at the airline’s maintenance station in Huntington, West Virginia], • “The FAA’s lack of oversight of Air Midwest’s compounded by the airplane’s aft center of gravity [CG], which maintenance program and its weight-and-balance was substantially aft of the certifi ed aft limit.” program.” The report said, “Contributing to the accident were: The accident airplane, manufactured and delivered to Air Midwest in 1996, had 15,003 fl ight hours and 21,332 cycles • “Air Midwest’s lack of oversight of the work being (each cycle comprises one takeoff and landing). During the two performed at the Huntington, West Virginia, maintenance days preceding the accident, maintenance was performed on station; the airplane at the Huntington station. • “Air Midwest’s maintenance procedures and “Air Midwest contracted with Raytheon Aerospace to provide documentation; mechanics, quality-assurance inspectors and a site manager for the [Huntington] maintenance station,” the report said. Air Midwest’s regional site manager worked the day shift at the “[Raytheon Aerospace] contracted with Structural Modifi cation Huntington station and was not present when the maintenance and Repair Technicians, Inc. (SMART) to supply the mechanic was performed on the accident airplane. The maintenance work force.” included visual inspections and servicing of the airplane’s major components, and one phase of a “detail six” (D6) maintenance check. The Air Midwest maintenance program included six D6 check phases, with a different phase conducted every 200 fl ight hours. The phase conducted during the two days preceding the accident comprised checks of the airplane’s elevator, rudder and trim tabs. On the night of Jan. 6, 2003, the quality-assurance inspector at the Huntington station was providing on-the-job training (OJT) to two SMART maintenance technicians (mechanics) who previously had not performed a complete D6 maintenance check. The quality-assurance inspector assigned one of the mechanics — who had performed rigging work on de Havilland Dash 8s — to check the tension of the elevator- control cables. “[The] quality-assurance inspector, who was providing the mechanic’s OJT, stated that he did not think he needed to closely supervise the mechanic because of his previous fl ight- control-rigging experience,” the report said. The D6 inspection procedures checklist (work card) indicated that cable tension was to be checked according to the elevator- control-system rigging procedure in the Beech 1900D Airliner Maintenance Manual. The report said that although interviews of offi cials of Air Midwest and Raytheon Aircraft Co. indicated that the entire elevator-control-system rigging procedure must be performed when cable-tension adjustments are made, neither the D6 work card nor the Beech 1900D maintenance manual “explicitly stated that the entire rigging procedure needed to be performed or that the elevator-cable-tension adjustment could not be accomplished as an isolated task.” The mechanic omitted several steps in the published rigging Raytheon Beech 1900D procedure; some of the steps were omitted with the quality- assurance inspector’s concurrence. The Beech 1900D is a twin-turboprop regional transport that entered service in 1991 and currently is manufactured by Raytheon Aircraft Co. The airplane is a derivative of the “[The quality-assurance] inspector stated, during a postaccident Beech 1900, which fi rst fl ew in 1982. The 1900D has a fl at interview, that he did not think the manufacturer intended for fl oor, a maximum cabin height of 5.9 feet (1.8 meters) and mechanics to follow the entire rigging procedure and that the 28.5 percent more cabin volume than its predecessor, the entire procedure had not been followed when past cable-tension Beech 1900C. Standard accommodation is for two fl ight crew members and 19 passengers. adjustments were made,” the report said. The airplane is powered by two Pratt & Whitney Canada As a result of the omitted steps, the elevator-control system PT6A-67D engines, each fl at rated at 1,279 shaft horsepower (954 kilowatts), and Hartzell four-blade, composite propellers. was incorrectly rigged during the D6 maintenance check, and Maximum takeoff weight is 17,120 pounds (7,766 kilograms). the incorrect rigging restricted the airplane’s elevator travel Maximum landing weight is 16,765 pounds (7,605 kilograms). to seven degrees nose-down — about one-half the downward Maximum cruising speed at 15,000 pounds (6,818 kilograms) travel specifi ed by the airplane manufacturer (i.e., 14 degrees gross weight and 25,000 feet altitude is 274 knots. Stalling speed at maximum takeoff weight with fl aps retracted is 101 to 15 degrees nose-down). knots.♦ “Examination of the accident airplane’s pitch-control-cable Source: Jane’s All the World’s Aircraft and Raytheon Aircraft Co. turnbuckles as found in the wreckage revealed that the AND [airplane-nose-down] turnbuckle, which measured 7.30 inches 2 FLIGHT SAFETY FOUNDATION • ACCIDENT PREVENTION • MAY 2004 [18.54 centimeters] in length, was extended 1.76 inches “According to postaccident interviews, neither the captain nor [4.47 centimeters] more than the ANU [airplane nose-up] the fi rst offi cer on those two fl ight legs noticed anything unusual turnbuckle, which measured 5.54 inches [14.07 centimeters] about the airplane,” the report said. in length,” the report said. “However, according to data from Air Midwest’s postaccident survey of its entire fl eet of 42 Flight 5481 was a regularly scheduled passenger flight Beech 1900D airplanes, the AND turnbuckle was extended, from Charlotte to Greenville–Spartanburg (South Carolina) on average, only 0.04 inch [0.10 centimeter] less than the International Airport. ANU turnbuckle. The captain, 25, had an airline transport pilot certificate “Ground tests showed that turnbuckles adjusted to the lengths of and approximately 2,790 fl ight hours, including 1,100 fl ight those found in the wreckage would result in limited downward hours as a Beech 1900D pilot-in-command. She was a fl ight elevator travel. … Adjustments to the cable turnbuckles (and instructor and fl ight-school supervisor before being hired by possibly other adjustable components ) during maintenance Air Midwest in March 2000. She earned a Beech 1900D type resulted in FDR [flight data recorder] measurements that rating in March 2001. showed a nine-degree AND loss of travel, which restricted the accident airplane’s elevator travel to seven degrees AND.” “In postaccident interviews, Air Midwest pilots who had fl own with the captain made favorable comments about her The report said that the quality-assurance inspector did not piloting skills,” the report said. “A check airman stated that the provide adequate OJT to the mechanic who adjusted the captain had no diffi culties during upgrade training and that she elevator-control system. demonstrated very good knowledge of the airplane’s systems and very good judgment. Another check airman described the “Insuffi cient training and supervision resulted in the mechanic captain as one of the better company pilots and stated that she making mistakes that led to the incorrect made very good decisions about fl ying. rigging and the restricted downward elevator travel,” the report said. “If the “Insuffi cient training “First offi cers stated that the captain was quality-assurance inspector had provided a thorough and methodical pilot who better training and supervision, the and supervision resulted controlled the airplane well and involved them likelihood of such errors would have been with the fl ight by asking for [their] opinions minimized.” in the mechanic making and letting them review paperwork.” mistakes that led to the The postmaintenance checks performed The first officer, 27, had a commercial by the quality-assurance inspector and incorrect rigging and pilot certifi cate and approximately 1,096 the mechanic did not include calibration fl ight hours, including 706 fl ight hours as