A BE1900D AFTER TKOF RETURNED TO THE FIELD DUE TO PAX RPT OF #1 ENG FORWARD COWLING LIFTING INFLT CAUSED BY OUTBOARD SIDE NOT LATCHED.

Narrative

XYZ WAS IN FOR SCHEDULED FUEL NOZZLE INSPECTION. WHEN THE ACFT WAS RUN FOR LEAK CHK; A XFER TUBE WAS FOUND TO BE LEAKING (FUEL NOZZLE INSPECTION IS NOT A REQUIRED INSPECTION ITEM). THE ACFT WAS BROUGHT BACK INTO THE HANGAR TO FIX THE PROB; THEN TAKEN BACK OUT. THE LEAK CHK WAS GOOD. THE ENG WAS RECOWLED OUTDOORS WITH ONLY OUTSIDE HANGAR LIGHTS AND FLASHLIGHT; IN TEMPS BTWN 20-30 DEGS F. APPARENTLY WHEN THE UPPER FORWARD COWLING WAS INSTALLED BY 2 MECHS; THE MECH THAT WAS ON THE INBOARD SIDE LOCKED HIS SIDE DOWN; BUT THE MECH ON THE OUTBOARD SIDE DID NOT. THE MECH WHO LATCHED HIS SIDE DOWN DID NOT CHK THE OPPOSITE SIDE ASSUMING THAT THE OTHER MECH HAD DONE SO. THE MECH THEN CLRED THE WORK ORDER DISCREPANCY AND BROUGHT THE LOG CAN AND WORK ORDER BOOK TO ME TO RELEASE THE AIRPLANE FOR FLT. PRIOR TO THE ACFT GOING OUT FOR ITS FIRST LEAK CHK I DID A FULL WALKAROUND ON THE ACFT. AFTER THE SECOND LEAK CHK; I VISUALLY INSPECTED THE COWLINGS AND THEY APPEARED TO BE LATCHED. I THEN RELEASED THE ACFT. JUST AFTER TKOF; A PAX NOTED THE COWLING LIFTING INFLT. THE ACFT RETURNED TO ZZZ WITH NO INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE MADE THE FINAL CLOSE UP INSPECTION AND DID NOT SEE THE OUTBOARD LATCHES WERE NOT LOCKED. THE RPTR SAID THE LATCH BOLT HEAD MUST ALIGN WITH A DECAL THAT IS ADJACENT TO EACH LATCH TO INDICATE THE LATCH IS LOCKED. THE RPTR STATED WHEN THE DECALS ARE NEW AND BRIGHT; THE LOCK INDICATION IS VISIBLE. THE RPTR SAID WHEN IN SVC FOR A SHORT PERIOD OF TIME THE DECALS ARE SOOTED UP; DIRTY AND PEELING OFF AND THIS CONDITION EXISTED ON THIS ACFT.