MAIN CARGO DOOR CAME AJAR AT ROTATION.

Narrative

MY CAPT AND I WERE IN LOS MOCHES; MEXICO. WE WERE IN A HURRY TO GET OUT OF THERE. WE LOADED THE ACFT WITH OUR PERSONAL BELONGINGS; AND SHUT THE CARGO DOOR. WE VERIFIED THE DOOR WAS SECURE; AND PUT THE CARGO NET UP. WE STARTED; RAN THROUGH OUR CHKS AND TAXIED TO RWY 9. WE WERE CLRED FOR DEP AND STARTED OUR TKOF ROLL. WE ROTATED AND I NOTICED A DOOR LIGHT. I CALLED 'WE HAVE A DOOR LIGHT;' AND 5 SECONDS LATER THE DOOR CAME AJAR BEING HELD ONLY BY THE CARGO NET. WE MADE A R TURN BACK TO THE ARPT AND LANDED ON RWY 27 WITH NO FURTHER INCIDENT. I BELIEVE WE COULD HAVE PREVENTED THIS IF WE HAD TAKEN A LITTLE MORE CAUTION IN SECURING THE DOOR. I ALSO BELIEVE THAT THERE MAY HAVE BEEN A MECHANICAL PROB AS WELL. THE COMPANY I WORK FOR HAS AN APPROVED DOOR CLOSING PROC WHICH IS SUPPOSED TO BE TAUGHT TO ALL CREW MEMBERS. TO THE BEST OF MY KNOWLEDGE; NO CREW MEMBER HAS RECEIVED THIS TRAINING. ALSO THIS IS NOT THE ONLY DOOR OPENING INCIDENT WITHIN THE COMPANY; AND THE OTHER INCIDENT CANNOT BE PROVEN TO BE PLT ERROR; BUT RATHER IS BELIEVED TO BE MECHANICAL MALFUNCTION. I THINK MORE STANDARDIZATION AND TRAINING SHOULD BE GIVEN IN THE CLOSING OF THE DOOR; AND ALSO A DIRECTIVE SHOULD BE ISSUED TO INSPECT AFTER MARKET CARGO DOORS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THE RPTR FLIES THE DASSAULT FALCON 20 THAT HAS BEEN MODIFIED WITH A LARGE FREIGHT DOOR. THE RPTR ADMITS TO BEING HURRIED BY HIS SCHEDULE TO GET THROUGH ANOTHER CITY AND THEN CLR CUSTOMS. THE DOOR WARNING LIGHT WAS OUT AT THE CONCLUSION OF THE PREFLT INSPECTION; BUT ILLUMINATED ON THE TKOF ROLL. A CARGO NET IS ATTACHED TO THE DOOR AND AIRFRAME AND PREVENTED THE DOOR FROM OPENING MORE THAN 1 FT. THE DOOR WAS WELL OFF OF THE LATCHES. THE RPTR STATES THAT THERE HAS BEEN AT LEAST 1 OTHER DOOR OPENING EPISODE IN HIS ACR AND SEVERAL OTHERS IN THE INDUSTRY. THERE IS A NEW DOOR WARNING SYS BEING INSTALLED THAT WILL CLOSE THE THROTTLES IF THE DOOR WARNING LIGHT ILLUMINATES ON TKOF ROLL. THE RPTR HAS HEARD NOTHING FROM THE FAA ON THIS. HE IS NOW AWARE OF THE FAA SAFETY HOTLINE.