LANCAIR IV ACFT CARGO DOOR LATCHES FAILED AFTER TAKEOFF RESULTING IN CARGO DOOR DEPARTING ACFT.

Narrative

TAKE OFF AT ZZZ; ROTATE; IN CLB AT 300 FT AGL RIGHT TURBOCHARGER FAILED; LOSS OF POWER. CONTINUED TO CLB TO SAFE ALTITUDE TO MAKE A SAFE TURN TO RETURN TO ARPT. IN TURN CARGO DOOR LATCH FAILED; RESULTING IN CARGO DOOR FALLING FROM ACFT. MADE SAFE LNDG AT ZZZ.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED HE LOVES THIS ACFT. HOWEVER; THE CARGO DOOR LATCHES APPEAR TO BE A PROBLEM. THE DOOR IS LOCATED ON THE L SIDE OF THE CARBON FIBER FUSELAGE. HIS ACFT IS NOT THE PRESSURIZED MODEL; SO HE HAS ONLY TWO LATCHES FOR THE CARGO DOOR. THE PRESSURIZED MODEL; KNOWN AS LANCAIR 4-P; MAY HAVE SIX LATCHES DUE TO PRESSURIZATION. THERE ARE TWO HINGES ON THE CARGO DOOR. ALL MODELS HAVE A PRESSURE SEAL AROUND THE CARGO DOOR THAT INFLATES USING A SMALL AIR PUMP. THE ORIGINAL CARGO DOOR LATCHES ARE THE TYPE THAT REQUIRE A KEY TO LOCK. RPTR STATED HE BELIEVES LANCAIR IS AWARE OF THE LATCH ISSUE; BUT ATTRIBUTES THE PROBLEM OF UNLATCHING TO OPERATOR ERROR. NEW REPLACEMENT LATCHES ARE AVAILABLE; AND ARE A DIFFERENT SPRING-LOADED TYPE WITH ATTACHMENT ARMS THAT CANNOT BE UNLATCHED IN-FLIGHT WHEN THE COCKPIT DOOR IS CLOSED. HE HAS NOT SEEN ANY SERVICE BULLETINS FROM LANCAIR ON THIS ISSUE. RPTR STATED HIS LANCAIR IS CLASSIFIED AS EXPERIMENTAL.