The aircraft, a DC-9-32, registered N904VJ, was the 496th DC-9 assembled at the Long Beach plant, was 27 years old at the time and had been previously flown by Delta Air Lines. Its first flight was April 18, 1969. Delivered to Delta on May 27, 1969, as N1281L, the airframe flew for Delta until the end of 1992, when it was retired and sold back to McDonnell Douglas. McDonnell Douglas then sold the plane to ValuJet in 1993. The aircraft was powered by two Pratt & Whitney JT8D-9A turbofan engines. The aircraft had suffered a series of incidents in the two years before the crash, including two aborted takeoffs and eight emergency landings. Engine and pressurization errors were the primary issues in several of the incidents. In May 1995, the FAA issued a re-wiring directive for all DC-9 cockpits because the wire bundles in the switch panel could cause "fire and uncontrolled smoke throughout the cockpit as a result of chafing and shorting." In the flight deck were two experienced pilots: Captain Candi Kubeck (35) and First Officer Richard Hazen (52). Captain Kubeck had accumulated 8,928 total flight hours throughout her career (including 2,116 hours on the DC-9) and First Officer Hazen had more than 11,800 total flight hours throughout his career, with 2,148 of them on the DC-9. On the afternoon of May 11, 1996, Flight 592 pushed back from gate G2 in Miami after a delay of 1 hour and 4 minutes due to mechanical problems. There were 105 passengers, mainly from Florida and Georgia, as well as a crew of two pilots and three flight attendants, bringing the total number of people on board to 110. At 2:04 PM EDT, 10 minutes before the disaster, the DC-9 took off from runway 9L (now runway 8R) and began a normal climb. The NTSB quickly determined that just before takeoff, 144 expired chemical oxygen generators, each slightly larger than the size of a tennis ball can, had been placed in the cargo compartment in five boxes marked COMAT (company material) by ValuJet's maintenance contractor, SabreTech, in violation of Federal Aviation Administration (FAA) regulations forbidding the transport of hazardous materials in passenger aircraft cargo holds. Failure to cover the generators' firing pins with the prescribed plastic caps made an accidental activation much more likely. The investigation revealed that rather than covering them, the cords attached to the firing pins were simply cut or duct-taped around the cans, and Scotch tape was also used to stick the ends down. SabreTech employees indicated on the cargo manifest that the "oxy canisters", which were loosely packed in the boxes that were each sealed with tape and bubble wrap, were "empty". ValuJet workers then loaded the boxes in the cargo hold in the mistaken belief that the devices that they contained were just empty canisters, thus being certified as supposedly "safe" to transport on a passenger aircraft, when in fact they were neither simple oxygen canisters, nor empty. Chemical oxygen generators, when activated, produce oxygen for passengers if the plane suffers a decompression. However, they also produce a great quantity of heat due to the exothermic nature of the chemical reaction involved. Therefore, not only could the heat and generated oxygen start a fire, but the oxygen could also keep the fire burning. The fire was worsened by the presence of two main aircraft tires (one of them mounted on a main wheel) and a nose tire and wheel that were also included in the list of materials shipped as COMAT. Investigators determined that one of the oxygen generators was likely triggered when the plane experienced a slight jolt while taxiing. As the aircraft taxied and took off, the activated generator got hotter and hotter. Soon, the boxes and surrounding packaging ignited, starting a fire. At 2:10 PM, the passengers started to smell smoke. At the same time, the pilots heard a loud bang in their headphones and noticed the plane was losing electrical power. The sag in electrical power and the