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Day
5
Season Five Research Files
Episode Twenty-one
3:00am - 4:00am
Pilots use four-digit codes on the plane’s transponder to communicate with air traffic control. Some codes are designated especially for emergencies.
The code “7500” means unlawful interference or hijacking, signaling that the plane needs assistance. If the plane alternates rapidly between the codes 7500 and 7700, the request is for urgent and armed intervention in the hijacking. The pilot may also call in the number during radio transmission. Air traffic control will respond back to confirm that this is what the pilot intended before sending help.
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