I'm simply asking a question.
I'm looking at the fact that the jet landed in Reno at 11PM. No one knew definitively that DBC had bailed until the flight crew looked in back.
Given this, how is it possible that the FBI--or anyone for that matter--started searching the next day? Also, did the search area shift over time as the first flight path came out--apparently on the 26th--and was subsequently updated?
Perhaps Bruce can pipe in on this.
If I remember correctly, the first LZ estimate was prepared the night of the hijacking and maybe even before the airliner got to Reno. I am referring to the one that names some people (however, their names are redacted).
In my personal and professional opinion, the 1971 FDR information would be essentially useless in determining a landing zone. In that age, such information was basically used to determine the sequence of events within a minute or so of a major event (such as an accident). The FDR would certainly not be able to provide conclusive proof of a jumper leaving the aircraft if even the flight crew couldn't tell for sure.
Further, the airliner, flight crew, and FDR didn't get back to Seattle until late on the afternoon of the 25th (Thanksgiving afternoon). Within just a handful of minutes, the flight crew was placed on an NWA airliner (which had been held for them) and were enroute to Minneapolis and got there late in the evening. Even if they had the FDR with them, someone in Minneapolis would have to work all night to predict the LZ from the FDR and other sources. So it is a very tight time line for a FDR supported LZ to be available on the morning of the 26th.