ralphchadkirk
Established Member
Not quite. Each aircraft transmits a 4 digit number code in order for Controllers to be able to differentiate between the dots on the screen. These are known as squawk codes. Some of these can be used to highlight an aircraft in distress, hijacked or with no communication. What happened here is that the pilot inadvertently squawked 7500 which is the hijack code, so the QRA typhoons responded appropriately.