PJ...
re your comments about how certain systems may get installed and certified in (what I will call) "other than Western" jurisdictions. I have very recently been involved (after the fact) in two different accidents -- both in Asia -- where installed and certified GPS and EGPWS databases were erroneous in terms of terrain heights and locations. One case involved enroute MSAs that had completely omitted (maybe still have?) a mountain that extends over 2000' above an MSA (!) on an approved route. The other case involves towers and trees missing from an approach database for a (non-precision) IFR runway. Interestingly, in that case the runway endpoint is also erroneously offset (tangentially) almost 400 meters in the database, on certified software and certified equipment.
I am not at all saying this is the case here (Smolensk), I am simply commenting on the fact that civil aviation standards and regulatory oversight in some parts of the world are very different than what many from "the West" are used to. Indeed, in some parts of the world -- regardless of what the charts, databases and AIPs may indicate -- one must use extreme caution (more than "normal caution") when operating at or near minimums of any sort.
grizz