How was I able to just plug in my headphones and listen to ATC and pilot chatter? I was travelling from Mumbai to Newark Liberty Intl on United Airlines 49, a Boeing  777-200. I was sitting in the economy section, last row, last seat to the plane's left, basically, I was literally the passenger on the last seat of the aircraft.

When I sat down, I plugged my earphones into the headphone jack and I could hear the conversation between ATC and the pilot, all I had to do was just twist the and hold the jack in a certain position. I could hear them talk to Mumbai ATC, the Islamabad ATC, Kabul ATC, even up to Iceland. My question is, how is this possible? What could have happened? Did the pilot or the airline know about this? Should I have told them about this? Is it illegal to listen to this chatter? Can this happen next time I travel or was I just lucky?
This is a feature offered on some United Airlines aircraft and flights. It's an interesting way to hear what's going on in the cockpit. You can find lots of information by searching for United channel 9.