On October 25, 1999, Learjet 35, registration N47BA, operated by Sunjet Aviation, Inc., of Sanford, Florida, departed Orlando (IATA: MCO, ICAO: KMCO) at 1319Z (0919 EDT) on a two-day, five-flight trip. Before departure, the aircraft had been fueled with 5,300 lb (2,400 kg) of Jet A, enough for 4 hours and 45 minutes of flight. On board were two pilots and four passengers.[1]
At 1327:13Z, the controller from the Jacksonville ARTCC instructed the pilot to climb and maintain flight level (FL) 390 (39,000 feet (12,000 m) above sea level). At 1327:18Z (0927:18 EDT), the pilot acknowledged the clearance by stating, "three nine zero bravo alpha." This was the last known radio transmission from the airplane, and occurred while the aircraft was passing through 23,000 feet (7,000 m). The next attempt to contact the aircraft occurred six minutes, 20 seconds later (14 minutes after departure), with the aircraft at 36,500 feet (11,100 m), and the controller's message went unacknowledged. The controller attempted to contact N47BA five more times in the next 4½ minutes, again with no answer.[1]
About 1454Z (now 0954 CDT due to the flight's crossing into the Central Time zone), a U.S. Air Force F-16 test pilot from the 40th Flight Test Squadron at Eglin Air Force Base, Florida, who happened to be in the air nearby, was directed by controllers to intercept N47BA. When the fighter was about 2,000 feet (610 m) from the Learjet, at an altitude of about 46,400 feet (14,100 m), the test pilot made two radio calls to N47BA but did not receive a response. The F-16 pilot made a visual inspection of the Lear, finding no visible damage to the airplane. Both engines were running, and the plane's red rotating anti-collision beacon was on (standard operation for aircraft in flight). The fighter pilot could not see inside the passenger section of the airplane because the windows seemed to be dark. Further, he stated that the entire right cockpit windshield was opaque, as if condensation or ice covered the inside. He also indicated that the left cockpit windshield was opaque, although several sections of the center of the windshield seemed to be only thinly covered by condensation or ice; a small rectangular section of the windshield was clear, with only a small section of the glare shield visible through this area. He did not see any flight control movement. About 1512Z, the F-16 pilot concluded his inspection of N47BA and broke formation, proceeding to Scott AFB, Illinois.[
