" As officials struggled Wednesday to explain why a jet with 150 people on board crashed in relatively clear skies, an investigator said evidence from a cockpit voice recorder indicated one pilot left the cockpit before the plane’s descent and was unable to get back in.
A senior military official involved in the investigation described “very smooth, very cool” conversation between the pilots during the early part of the flight from Barcelona to Düsseldorf. Then the audio indicated that one of the pilots left the cockpit and could not re-enter.
“The guy outside is knocking lightly on the door and there is no answer,” the investigator said. “And then he hits the door stronger and no answer. There is never an answer.”
He said, “You can hear he is trying to smash the door down.”
QUESTION: What are some possible explanations; what is their relative (comparative) plausibility; and what further evidence would you seek to strengthen or weaken each possible explanation?
1. The pilot in the cockpit had had heart attack. (Alternative: He or she had a stroke. Etc.)
2. A terrorist (or flight attendant) forced the pilot in cabin to crash the plane. (Variants of this explanation.)
3. The pilot in the cabin decided to crash the plane. (Etc.)