Rotormat
I am afraid that your inexperience on international industry requirements shows by your assumption that all aircraft are equipped equally.
In the USA, there is no AVAD requirement legistlatively,. Customers can want it, but it is not certified by the FAA so not as easy as you might think.
There are many discrepancies between the FARs, CARs and ICAO.
Aircraft in the GOM still fly with one way fuel to some places....try getting that approved in UK or Australia. The world is not a level playing field in terms of equipment and even customer requirements I'm afraid.