A MOONEY'S BAGGAGE DOOR POPPED OPEN DURING TKOF AFTER THE FORE AND AFT PINS DID NOT MOVE TO ENGAGE. THE LATCH WAS IN THE CLOSED POSITION AND THE DOOR APPEARED CLOSED DURING PREFLT.

Narrative

PREFLT DONE ON M20J PER USUAL ROUTINE IN LIGHT RAIN PRIOR TO DEPARTING. BEGAN TKOF ROLL. AT OR SHORTLY AFTER ROTATION; NOTICED BRISK AIR FLOW IN COCKPIT. USING 'ANR' HEADSET; SO DID NOT NOTICE ANY UNUSUAL SOUND. GLANCING AROUND; HOWEVER; SAW THAT BAGGAGE DOOR HAD POPPED OPEN. BECAUSE OF CONCERN ABOUT LINED UP ACFT BEHIND ME POSSIBLY ROLLING; ELECTED TO CONTINUE TKOF; MADE STANDARD L PATTERN; AND LANDED UNEVENTFULLY TO SECURE DAMAGED DOOR AND REMOVE WET INSULATION FROM EMPENNAGE. INSPECTION OF ACFT REVEALED NO SIGNIFICANT DAMAGE OTHER THAN TO DOOR. M20J BAGGAGE DOOR IS PIANO HINGED AT TOP AND CLOSES DOWN SNUGLY AND FLUSH TO OUTER SKIN OF FUSELAGE. LATCH WHEN MOVED TO FLUSH; 'CLOSED' POS ACTIVATES FORE AND AFT PINS THAT SECURE LOWER PORTION OF DOOR TO DOOR FRAME IN FUSELAGE. LATCH IS USUALLY NOT LOCKED IN CASE OF REQUIREMENT FOR EMER EXTRICATION. BAGGAGE DOOR OF INCIDENT ACFT LATE MODEL (ORIGINAL EQUIP IN 1995 M20J MSE) WITH INTERIOR LATCH RELEASE SAFETIED BY COTTER PIN. BAGGAGE DOOR OF INCIDENT ACFT SUBSEQUENTLY REMOVED BY MAINT FACILITY. EXTERIOR DOOR SKINS AND TOP OF FRAME ADJACENT TO PIANO HINGE DEEMED TOO DAMAGED FOR ECONOMICAL REPAIR. UPON CYCLING INTACT AND EVIDENTLY UNDAMAGED LOCK MECHANISM; FAILURE MODE IDENTED BY A&P IN WHICH FORE AND AFT PINS DID NOT MOVE TO ENGAGED; 'CLOSED' POS DESPITE LATCH BEING IN APPROPRIATE 'CLOSED' POS. SUSPECT INCIDENT RESULTED FROM THIS FAULT IN THE LATCH; SINCE BEST RECOLLECTION OF PLT IS THAT PREFLT WAS UNREMARKABLE AND LATCH WAS IN CLOSED; FLUSH POS. POPPED BAGGAGE DOORS HAVE BEEN PREVIOUSLY RPTED IN MOONEY ACFT AND SEVERAL MODIFICATIONS HAVE BEEN MADE TO THE LATCHING MECHANISM IN ATTEMPTS TO CORRECT THIS PROB. APPARENTLY; THERE IS OPPORTUNITY FOR FURTHER IMPROVEMENT. THIS IS A SAFETY HAZARD. ALTHOUGH THE OPEN DOOR DID NOT ADVERSELY AFFECT THE ACFT'S HANDLING; IT WAS CERTAINLY A DISTR TO THE PLT IN A CRITICAL PHASE OF FLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT HE IS ABOUT 99% CERTAIN THAT THE DOOR WAS CLOSED AND LATCHED PRIOR TO FLT. IN HIS CASE THE ACFT WAS PERFECTLY FLYABLE BUT HE UNDERSTANDS THAT THERE HAS BEEN AT LEAST ONE EVENT THAT RESULTED IN AN ACCIDENT DUE TO PILOT DISTRACTION. HE COMMENTED THAT HE WAS DISTRACTED BUT THAT HE MERELY CONTINUED FLYING THE ACFT WITH A KNOWN PROBLEM. THE DOOR WAS BADLY BATTERED IN THE WIND AND IS BEING REPLACED.