Investigation Summary
The investigation revealed a chain of systemic failures involving ValuJet and its maintenance contractor, SabreTech. The oxygen generators, which were expired but still contained chemical cores, were removed from other aircraft and sent to the shipping department without safety caps. They were mislabeled as 'Oxy Canisters - Empty' and loaded into the forward Class D cargo hold alongside several aircraft tires. During taxi or takeoff, one or more generators were jostled and activated, reaching temperatures up to 500 degrees Fahrenheit. In the oxygen-rich environment of the hold, the fire spread rapidly to the tires and other cargo. Because Class D holds were designed to be airtight rather than equipped with detectors, the crew was unaware of the fire until smoke entered the cockpit and cabin, by which time the fire had already burned through flight control cables and the cabin floor. The severity of the oversight led to unprecedented legal action; SabreTech became the first aviation maintenance company to face corporate criminal charges in a U.S. air disaster, with federal indictments also brought against three of its employees.
Final Conclusions
The NTSB determined the probable cause was a fire in the airplane's forward cargo compartment that was initiated by the activation of one or more chemical oxygen generators that were improperly packaged and carried. Contributing to the accident was the failure of SabreTech to properly prepare the generators for transport, ValuJet's failure to oversee SabreTech's hazardous materials program, and the FAA's failure to require smoke detection and fire suppression systems in Class D cargo compartments.
Video Analysis
I Can't Believe they put THIS onboard! | Valujet flight 592 — A detailed look at the ValuJet 592 disaster, exploring how improperly handled chemical oxygen generators led to a catastrophic fire in the Everglades.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
Chemical Oxygen Generator
A device that produces oxygen through an exothermic chemical reaction; when activated, it reaches temperatures of 450-500°F.
Class D Cargo Compartment
A cargo hold designed to be airtight to suppress fire by oxygen depletion; this design failed due to the oxygen produced by the generators.
Flight Control Cables
Mechanical cables running beneath the cabin floor that were damaged or severed by the intense heat of the cargo fire.
Interesting Facts
- 01The aircraft was 27 years old and had previously been operated by Delta Air Lines.
- 02The cargo hold contained approximately 130 expired chemical oxygen generators, most lacking safety caps, packed into five boxes.
- 03Class D cargo compartments at the time relied on oxygen starvation to extinguish fires and were not required to have smoke detectors.
- 04The fire was so intense that it caused a main landing gear tire in the hold to explode, which was the 'bang' heard by the pilots.
- 05ValuJet merged with AirTran Airways in 1997, adopting the AirTran name to distance itself from the crash's reputation.
Safety Actions & Advisories
Cargo Hold Retrofits
The FAA mandated the installation of smoke detection and fire suppression systems in all Class D cargo compartments, effectively eliminating the Class D category in favor of Class C standards.
Hazardous Materials Regulation
Strict new rules were implemented regarding the transport of chemical oxygen generators, including a ban on carrying them as cargo on passenger aircraft unless they are rendered completely inert.
Known Controversies & Unanswered Questions
Criminalization of Aviation Accidents
Reference ↗The criminal prosecution of SabreTech and its employees was highly controversial within the aviation industry. Critics, including some safety experts, argued that criminalizing maintenance errors would discourage workers from reporting mistakes, thereby undermining the 'just culture' necessary for aviation safety. While SabreTech was convicted on several counts, the convictions of the individual employees were largely overturned or resulted in acquittals, and the company eventually reached a settlement.