THE MAIN CARGO DOOR CAME OPEN INFLT ON A B727 FREIGHTER.

Narrative

AFTER TKOF FROM RWY 8R AT ATL; MAIN CARGO DOOR CAME OPEN INFLT. CLBED TO 3000 FT MSL AND TURNED DOWNWIND AFTER NOTIFYING TWR. WE OBTAINED PERMISSION FROM APCH CTL TO DUMP FUEL AND RAN THE APPROPRIATE CHKLISTS. PERFORMED NORMAL APCH AND LNDG ON RWY 8R. AFTER SHUTDOWN; PERFORMED POSTFLT INSPECTION; FOUND DOOR OPEN APPROX 2 FT; BUT NO STRUCTURAL DAMAGE. SUPPLEMENTAL INFO FROM ACN 290895: THE DOOR WAS CHKED BY THE SO VISUALLY AND MAINT AS CLOSED AND LOCKED. THERE APPEARED TO BE A PROB WITH THE INDICATING SYS INSIDE THE COCKPIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES THE B727 FREIGHTER FOR A MAJOR FREIGHT AIRLINE. THE SO; AN SO CHK AIRMAN AND A MECH ON THE GND; ALL LOOKED AT THE DOOR BEFORE DEP AND SAW THAT IT WAS PROPERLY CLOSED. THE RPTR STATES THAT THERE WAS A SERIES OF 3 ELECTRICAL FAILURES THAT CAUSED THIS INCIDENT INCLUDING THE DOGS DID NOT ROTATE OVER CTR TO CAPTURE THE DOOR AND A RELAY ON THE SO PANEL FAILED ALLOWING THE WARNING LIGHT TO SHOW THE DOOR CLOSED WHEN THE LOCKING SEQUENCE HAD NOT COMPLETED. AFTER TKOF; THE RELAY ALLOWED THE WARNING LIGHT TO ILLUMINATE SHOWING THE DOOR NOT LOCKED. THE CHK AIRMAN LOOKED AT THE DOOR TO SEE THAT IT WAS OPEN. THE AIR NOISE GAVE THEM ANOTHER CLUE. THE ACFT WAS KEPT BELOW 190 KTS. THERE WERE NO CTL PROBS. THERE WAS NO CONSEQUENTIAL DAMAGE TO THE DOOR OR ANY PART OF THE ACFT.