ILS/VOR Confusion
Regarding the discussion of the possibility of the AC flying the approach to the VOR instead of the ILS, it has been done before and therefore possible. The location and elevation of the wreckage is consistent.
I was an air traffic controller in YXS during the mid 70's when a CP Air 737 flight from YXJ nearly flew into Tabor Mnt. doing this very thing. Both pilots were fired.
For this to occur, both pilots have to fail to carry out the check list duties. Nevertheless, it happens.
The ancient FDR will only provide basic info so it will be of limited utility.