The people aboard had passed through Copenhagen Airport on the afternoon of January 26. What happened in the baggage handling and security processes at Copenhagen during that stopover would become, in the subsequent investigation, one of the central questions of the entire case. Witnesses later reported that a passenger’s behavior had been noticed as unusual by staff at Copenhagen Airport. The investigation would focus on what had been loaded onto the aircraft during the Copenhagen ground stop.
None of the twenty-seven people who died in the crash left any recorded statement about their experience in the minutes before the explosion. The historical record of the final forty-six minutes of Flight 367 is held almost entirely in the data captured by the aircraft’s flight recorders and in the physical evidence analyzed by investigators in the weeks after.
## The Explosion: 4:01 p.m., 33,330 Feet
The DC-9-32 was cruising at altitude when the explosion occurred. At approximately 4:01 p.m., a device detonated in the forward baggage compartment of the aircraft. The Czechoslovak Civil Aviation Authority’s investigation, which produced the official accident report, attributed the explosion to an improvised explosive device — a bomb concealed in carry-on luggage placed in the forward baggage compartment.
The specific mechanics of what a bomb detonation does to a pressurized aircraft at altitude are well understood from multiple incidents and extensive investigation. A commercial aircraft at cruising altitude maintains cabin pressure roughly equivalent to the ambient pressure at approximately 6,000 to 8,000 feet, even though the aircraft may be flying at 35,000 feet. The difference between internal cabin pressure and external atmospheric pressure at altitude is significant. When a bomb detonates in a pressurized compartment, the energy of the explosion combines with this pressure differential in a way that can cause catastrophic structural failure far beyond what the explosive yield alone would produce.