This is the single most powerful piece of direct evidence against the shootdown theory. The flight recorder is an objective device; it records what the aircraft was doing, not what anyone wished had been happening. The data it captured — reviewed by experts from Czechoslovakia, Yugoslavia, and additional countries, in a multi-national technical review conducted in Amsterdam — is the strongest available basis for confidence in the official conclusion that the breakup occurred at cruising altitude.
The cockpit voice recorder evidence is less discussed in the public accounts of the case, possibly because the recording itself has not been publicly disclosed. What we know from the investigation is that the cockpit voice recorder was recovered and analyzed. Its content — the audio of the final moments on the flight deck — would contain whatever was said or heard on the flight deck in the seconds before the explosion. The official investigation did not report hearing any communications consistent with a military intercept prior to the detonation.
The debris field is the second significant piece of physical evidence. A debris field extending more than 1.5 kilometers — as reported in accounts of the crash scene — is consistent with a breakup at high altitude. When an aircraft breaks apart at high altitude, the individual pieces separate in the air and are carried varying distances by wind and aerodynamic forces as they fall. The result is a wide debris field. A breakup at low altitude produces a much more concentrated field because there is less time for pieces to separate during the descent. The extended debris field at Srbská Kamenice is consistent with a high-altitude breakup and inconsistent with a low-altitude event.