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March 26, 2001

NTSB Advisory National Transportation Safety Board Washington, DC 20594

NTSB ISSUES FACTUAL INFORMATION ON EMBRAER-120 UPSET EVENT NEAR FLORIDA

The National Transportation Safety Board today released factual information on an upset event involving a turboprop aircraft last week near Florida. On March 19, 2001, about 1830 eastern standard time, the flight crew of Comair flight 5054, an EMB-120, "Brasilia," reported experiencing an upset event after encountering icing conditions. The aircraft was 46 minutes into a scheduled flight from Nassau, Bahamas, to Orlando, Florida. The airplane diverted to West Palm Beach, Florida. Examination of the aircraft found substantial damage to the elevators and the horizontal stabilizer. There were no injuries to the flight crew or 25 passengers. The Safety Board has assigned Mr. Al Dickinson as the Investigator-in-Charge. NTSB specialists have been assigned to the investigation in the areas of airworthiness, operations, air traffic control, meteorology, human performance, survival factors, aircraft performance, flight data recorder, and cockpit voice recorder. As the aircraft was manufactured in Brazil, the Brazilian authorities have assigned an accredited representative to assist in the investigation, with Embraer, the manufacturer of the airplane, providing a technical advisor. Parties to the investigation are the Federal Aviation Administration, Comair, and the Air Line Pilots Association. The flight crew was interviewed and provided the following information: * The captain had about 16,000 hours total flight time, including about 9,000 in the EMB-120, and was the flying pilot during this accident. The first officer had about 1,350 hours total flight time, including about 250 hours in the EMB-120. * * The crew reported that the airplane's systems, including its ice detection and anti ice systems, functioned normally before the upset. * * They indicated that the airplane was being controlled by the autopilot at about 18,000 feet when they encountered instrument meteorological conditions that rapidly led to the windscreen being covered by a layer of ice. * * The crew turned ice protection systems on and the ice on the windshield was cleared. * * The first officer observed ice on the right wing's boots and the right prop's spinner that extended farther back than he had previously experienced. The first officer switched the ice protection systems to their highest settings. * * The first officer notified the captain of a decrease in airspeed from about 175 to 160 knots. * * The captain disconnected the autopilot, applied power, and initiated nose down pitch inputs to arrest the airspeed loss. They indicated that these actions were unsuccessful and the speed further deteriorated to about 130 knots at which point the airplane experienced oscillations about its pitch, yaw, and roll axes and subsequently rolled sharply to the right and entered a steep descent. * * During the descent, the electronic attitude display indicators in the airplane were observed to intermittently present no useful information. The captain stated that, "when we needed it [the electronic attitude display indicators] the most we didn't have it." * * The airplane descended between cloud layers into visual conditions where recovery occurred about 10,000 feet. * * After the recovery, no anomalies with the airplane, its handling characteristics, or its systems were noted. * * The airplane diverted to West Palm Beach where a precautionary landing was made. * * The flight data recorder and the cockpit voice recorder have been examined at the Safety Board's laboratory. The cockpit voice recorder continued to run after the landing and did not provide any useful information regarding the upset. The accident airplane's solid state 25-hour FDR captured the event and functioned until power was removed on the ground. Preliminary review of the FDR data indicate the following sequence of events: * * The airplane was at about 17,000 feet, with the airspeed stabilized around 200 knots indicated airspeed (kias). The autopilot was engaged. * * The airspeed slowed from about 200 kias to 180, and the airplane began trimming nose-up. * * The airspeed continued to decrease to about 140 kias while trimming to a nearly full nose-up position. * * The autopilot disconnected and the airplane rolled about 90 degrees to the left, and then back to near level. In the next 24 seconds, the airplane again rolled about 110 degrees to the left, back to level, then about 120 degrees to the right, back to level, and then rolled 360 degrees to the right, back to near wings level. Since the crew reported trouble with the flight attitude instruments, the roll angles recorded on the FDR are being further investigated. * * The maximum nose down pitch attitude was 60 degrees, the maximum recorded airspeed was about 240 kias, and maximum vertical acceleration during recovery was about +3.6 g. * * The airplane landed about 12 minutes after the start of the upset.