AN ACR DC9 TOOK OFF WITH ITS AFT CARGO DOOR OPEN.

Narrative

GND CREW FAILED TO SECURE AFT CARGO DOOR AND TOLD US 'WALKAROUND COMPLETE; ALL DOORS CLOSED.' AFT CARGO DOOR MICRO-SWITCH FAILED AND DID NOT SHOW DOOR OPEN ON COCKPIT OVERHEAD ANNUNCIATOR LIGHT PANEL (LIGHT TESTED OK ON PUSH TO TEST). COULD NOT PRESSURIZE. FLEW TO IAH AT 10000 FT. IAH GND PERSONNEL INFORMED US WE HAD ARRIVED WITH REAR CARGO DOOR OPEN. IT APPEARED ALL CARGO IN AFT COMPARTMENT REMAINED INSIDE. THIS SIT OCCURRED DUE TO GND CREW NOT CONDUCTING THEIR REQUIRED CHKS AND A FAULTY CARGO MICRO SWITCH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES THE DC9. THE GND CREW CHK THAT CONCLUDES WITH 'WALKAROUND COMPLETE; ALL DOORS CLOSED' IS SOP FOR HIS ACR. IAH MAINT PERSONNEL CONFIRMED THAT THE DOOR PROX SWITCH HAD FAILED. THE RPTR HAS NOT HEARD FROM THE FAA ON THIS MATTER. THERE WAS NO ACFT DAMAGE. SUPPLEMENTAL INFO FROM ACN 366063: PRIOR TO BEING PUSHED BACK FROM THE GATE IN BRO; THE CAPT ASKED THE TUG DRIVER IF ALL THE ACFT DOORS AND ACCESS PANELS HAD BEEN VISUALLY CHKED AND CONFIRMED CLOSED; HIS RESPONSE WAS YES; ROGER SIR. THE CAPT THEN CHKED THE ANNUNCIATOR PANEL TO VERIFY THAT THE DOOR LIGHTS WORKED; AND THEY DID INDICATE THAT ALL THE DOORS WERE IN FACT CLOSED. AFTER WE DEPARTED BRO WE ENCOUNTERED A PRESSURIZATION PROB. WHILE ENRTE WE PERFORMED ALL THE ABNORMAL CHKLISTS WITHOUT CORRECTING THE PROB. THE CAPT THEN TALKED WITH MAINT CTL AND THEY WERE SATISFIED THAT A COLD AIR DUCT HAD COME LOOSE CAUSING THE PROB. THEIR SUGGESTION WAS TO CONTINUE ON TO IAH AS LONG AS IT WAS JUST A PRESSURIZATION PROB. WE WERE ABLE TO MAINTAIN A CABIN ALT OF 9200 FT. UPON ARRIVING AT THE GATE IN IAH; WE WERE INFORMED THAT OUR AFT CARGO DOOR WAS OPEN. MAINT INFORMED US THAT THE MICROSWITCH ON THE AFT CARGO DOOR HAD FAILED. THE FAILURE OF THIS SWITCH CAUSED THE ANNUNCIATOR PANEL LIGHT TO REMAIN OFF AT ALL TIMES REGARDLESS OF DOOR POSITION. THE LIGHT WOULD ONLY COME ON WHEN THE ANNUNCIATOR PANEL WAS TESTED. OUR MANIFEST INDICATED THAT BRO HAD LOADED 51 BAGS IN THE AFT BIN; BUT WHEN THEY WERE COUNTED IN IAH; THERE WERE 56 BAGS AFT. THE TUG DRIVER IN BRO DID NOT DO THE REQUIRED WALKAROUND OF THE ACFT TO CHK ALL THE DOORS AND ACCESS PANELS WERE CLOSED PER OUR SOP.