A CESSNA 421 DURING A REJECTED TKOF EXPERIENCED A RWY EXCURSION CAUSED BY AN UNLATCHED CARGO DOOR COMING OPEN.

Narrative

DURING PREFLT; THE FORWARD L NOSE BAGGAGE DOOR WAS OPENED AND LEFT UP. A LINE PERSONNEL ADDED ENG OIL AND FUELED THE ACFT. AT SOME POINT HE CLOSED THE NOSE BAGGAGE DOOR BUT DID NOT LATCH IT. HE LATER STATED THAT HE THOUGHT I WOULD BE LOADING LUGGAGE. DURING THE TKOF; JUST AFTER ROTATION AND LIFTOFF; THE L FRONT BAGGAGE DOOR CAME OPEN. I CLOSED THE THROTTLES; PUT THE ACFT ON THE RWY; AND APPLIED THE BRAKES. RWY 19 AT JWN IS DOWNHILL; AND STEADY RAIN WAS FALLING. BRAKING ACTION WAS POOR. THE ACFT OVERRAN THE END OF THE RWY BEFORE COMING TO A STOP. THERE WAS NO DAMAGE. THE ACFT WAS TOWED BACK TO THE RAMP. MY PROC CONCERNING BAGGAGE DOORS IS TO LEAVE THEM OPEN DURING LOADING; THEN DOORS ARE CLOSED AND LATCHED. I NEVER CLOSE DOORS WITHOUT LATCHING THEM. THIS ROUTINE WAS INTERRUPTED BY LINE PERSONNEL. IT SEEMED MORE PRUDENT TO ABORT THE TKOF RATHER THAN FLY THE PATTERN OR APCH WITH THE DOOR OPEN. MY TRAINING IN THIS ACFT HAS EMPHASIZED THE IMPORTANCE OF ABORTING THE TKOF IN THE CASE OF ENG FAILURE OR OTHER SERIOUS PROBS IF THE LNDG GEAR IS NOT UP OR IN TRANSIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A CESSNA 421. THE RPTR SAID THE DECISION TO REJECT THE TKOF WAS THE CARGO DOOR WAS LOCATED ON THE L SIDE OF THE NOSE IN FRONT OF THE WINDSHIELD. THE RPTR SAID IT WAS QUESTIONABLE IF THE DOOR WOULD REMAIN ATTACHED IF THE ACFT WAS FLOWN AND IF IT DEPARTED IT MAY HAVE TAKEN OUT THE L WINDSHIELD OR PENETRATED THE COCKPIT INTERIOR. THE RPTR STATED NO DAMAGE WAS DONE TO THE ACFT IN THE RWY EXCURSION BUT THE ENTIRE EVENT SURE SCARED HIM.