AN LR60 MADE 2 ATTEMPTS TO TAKE OFF AND ABORTED BOTH DUE TO THE TKOF WARNING HORN SOUNDING. FOUND PARKING BRAKE WARNING LIGHT CIRCUIT FAILED.

Narrative

AFTER BEING CLRED FOR TKOF ON RWY 30; THE BEFORE TKOF CHKLIST WAS COMPLETED AND; THUS; WE PROCEEDED UNDER NORMAL CONDITIONS WITH THE TKOF. THE TKOF WARNING HORN SOUNDED AND THE TKOF WAS ABORTED AND TWR WAS NOTIFIED. NO ASSISTANCE REQUIRED. ASSUMING THAT SOMETHING ON THE BEFORE TKOF CHKLIST HAD BEEN MISSED; THE CHKLIST WAS COMPLETED AGAIN. IN FINDING NOTHING OUT OF THE ORDINARY; THE CONSENSUS WAS TO RE-ATTEMPT THE TKOF. AGAIN; AFTER BEING CLRED FOR TKOF; THE BEFORE TKOF CHKLIST WAS COMPLETED AND; THUS; WE PROCEEDED WITH A NORMAL TKOF. AS WITH THE FIRST ATTEMPT; THE TKOF WARNING HORN SOUNDED AND THE TKOF WAS ABORTED; AT WHICH POINT; IT WAS DECIDED TO RETURN TO THE RAMP AND REASSESS THE SITUATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT MAINT FOUND THE PARKING BRAKE WARNING LIGHT CIRCUIT HAD FAILED. THE BULB WAS REPLACED AND IT WAS FOUND THE SOCKET MAY HAVE BEEN DEFECTIVE. THE RPTR STATED THAT THIS CIRCUIT AND THE PARKING BRAKE CIRCUIT ARE AN INPUT TO THE TKOF WARNING SYS IN ADDITION TO STABILIZER AND SPOILERS. RPTR NOTED THAT THE PARKING BRAKE WARNING SYS IS NOT ON THE TKOF CHKLIST.