What happened
During the climbout phase from Miami, the aircraft encountered a sudden cabin pressurization issue. The crew immediately donned their oxygen masks, and the cabin altitude stabilized at 20,000 feet as the plane leveled off at 33,000 feet. Approximately forty minutes before reaching the destination, a flight engineer trainee, who was acting as an observer, asked the first officer about the remaining flight time. Shortly after this inquiry, the trainee began to slump and lose consciousness.
The flight engineer exchanged oxygen masks with the trainee and confirmed that the oxygen supply was functioning normally. An emergency descent was initiated to 6,000 feet while first aid was administered onboard. Upon arrival at the destination, an ambulance met the aircraft and transported the trainee to a hospital, where he later died. The cause of death was diagnosed as aerobolism by exclusion.
The investigation
The pressurization failure was reportedly linked to a stuck outflow valve. This mechanical issue prevented the cabin pressure from being maintained at safe levels during the climbout, leading to rapid decompression. The crew's prompt use of oxygen masks stabilized the environment for most passengers and crew, but the trainee had already suffered severe physiological effects.
Findings
The investigation revealed that the trainee had a clinical history of seizures and loss of consciousness following decompression events. This medical background likely contributed to the severity of his reaction to the pressure drop. The stuck outflow valve was identified as the primary mechanical cause of the pressurization problem. No other mechanical failures or crew errors were cited in the immediate sequence of events leading to the incident.