Door lock system

A security system adapted for use on an aircraft to prevent unauthorized access into a cockpit area of the aircraft via a cockpit door. The system includes a keypad accessible by individuals in a cabin area of the aircraft. A logic system is in communication with the keypad and also with a switch disposed inside the cockpit. Occupants of the cockpit, via the switch, have the ability to manually unlock the cockpit door, to deny the request for entry, or to do nothing, in which case the door will be automatically unlocked after the expiration of a predetermined time interval. No amount of tampering with the keypad or destruction of the keypad can unlock the cockpit door if the cockpit occupants decide to deny a request for entry via appropriate positioning of the switch. A pressure sensor in communication with the controller allows the door to be automatically unlocked in the event of a decompression condition occurring in the cockpit.