The FAA had earlier referred to it as a "damaged database file". Which I suspect translates to something like a index file + data file pair, or a raw file for

The FAA had earlier referred to it as a "damaged database file". Which I suspect translates to something like a index file + data file pair, or a raw file for some kind of database. It sounds like the contractors accidentally overwrote something like that. So, yes, the system should have thrown some kind of "invalid magic number" or "unable to read header" error. Though that would have probably only helped a little. They were still slow to recover even after they understood the issue. Meaning they are missing still other things, like procedures to start over using fresh data. They had, for example, lots of partners that already had all the "known good data before the issue", but no way to take that and run.