If the engines are still running the search footprint has to encompass the fuel range. If the engines aren't running the range may still be 50+ miles.

As for pilot radio contact: remember that Air France flight 447 crashed without the pilots ever making a radio call despite plenty of time & ability to do so.

One problem here is that nobody knows who has jurisdiction until the plane is found. So nobody is releasing information on things like autonomous radio calls by the maintenance system. Once there's someone in charge evidence will be collected & disseminated in a more orderly manner.

I'm not ready to make too much of the stolen passport issue yet. How common it is in that part of the world? Traveling on false paperwork offends TSA sensibilities but that may have no bearing on "local" flights in that part of the world, especially if minorities are able to upgrade their treatment by carrying a first-world passport.