[robert14]

None of the 777 expert talking heads I have listened to for the past 6 days have even mentioned the AHM let alone how it works. I am an aerospace engineer and experienced pilot. I did not know about the AHM until I started google searching AHM and ping yesterday.

[virgil]

Well, I'm glad we have someone here who knows a lot about aircraft. Have you flown these big jets? I just think the First Officer would know about all of these tracking systems, IMHO. Anyway, unless there's a way to turn off that AHM transponder, it doesn't bode well for the aircraft and passengers.

If they could turn it off, an ideal time for a hijacker to do so would be after the first 2 pings and right before the last ping to make everybody think it's crashed. Some of these terrorists are pretty crafty.