Not a pilot, but pretty sure either you cannot turn off the transponder, or at the very least, it requires a deliberate manual act. The fact that the transponder was off is most concerning.
You would think there would have been radio contact. Unless a pilot was in on the scam.
Both pilots have moslem names.
Look it up.
As an example, Nidal Hasan was a US army Major before he ‘suddenly’ began screaming in Arabic and massacred Fort Hood.
Moslems aren’t serial killers until they are.
Yes, you can turn off the transponder with the switch or by pulling the circuit breaker.
The transponder can be turned off by the pilot or anyone in the cockpit that knows how to do so.
It used to be turned on at the end of the runway just before departure. However, the FAA now recommends it be turned on before start of taxi, so aircraft is visible to ATC surveillance systems while on the airport.
You are also supposed to put the transponder briefly into "standby" mode whenever changing the ATC-assigned transponder code. This prevents an inadvertent alert if the transponder is briefly set to 7500, 7600, or 7700 -- various emergency codes.
I thought that if the transponder was turned off, it triggered an automatic hijack alert.