The vehicle was manned by a crew of two, positioned in separate cockpits squeezed into empty areas in the airframe.
Up another metal ladder was the cockpit and a separate cramped, windowless space for the electronic warfare officer — Poppa, 28, from San Diego.
In a separate development, the Dutch air safety board said the cockpit voice recorder from flight MH17 had been successfully downloaded and contained "valid data from the flight".
The cockpit for the student would have been positioned ahead of the instructor's cockpit and each would have had a separate canopy.
The most significant difference between the XAJ-1 and the production aircraft was the revision of the cockpit to accommodate a third crewman in a separate compartment.
A pilot on a separate flight reported in November a similar descent and hearing the same warnings in the cockpit, and said neither of the pilots on board was able to find an inappropriate setup.
A separate report by Russian experts blamed the Polish crew and the alleged presence of a Polish air force commander in the cockpit, suggesting he might have pressed for a landing in spite of bad weather conditions.
