What was found
ACFT ON FINAL APPROACH, WHEN PILOT HEARD A THUD. STATED HE THOUGHT HE HAD HIT A BIRD. UNEVENTFUL LANDING WAS MADE. PILOT DEPARTED AC AND FOUND LT ENGINE TOP COWLING HAD COME OPEN. MX FOUND OUT, BAD LATCHING MECHANISM BROKE. SUSPECT LATCH BROKE AND THE COWLING BLEW OPEN ENOUGH FOR THE OTHER LATCH TO OPEN, ALLOWING TOP COWL TO BLOW BACK IN AIRSTREAM. THE BACK HINGE AND ALL LATCHES WERE REPLACED WITH SERVICEABLE PARTS. (K)