What was found
DURING CRUISE FLIGHT, THE AIRCRAFT SHUDDERED LIGHTLY AND THE PILOT SAW A FLASH OF WHITE. THE NR 1 ENGINE TOP FORWARD COWLING DISENGAGED FROM THE AIRPLANE. INITIAL THOUGHT WAS A BIRD STRIKE, BUT THERE WAS NO VISIBLE EVIDENCE. THE ENGINE INSTRUMENTS WERE MONITORED CLOSELY AND NO ABNORMAL ENGINE INDICATIONS WERE NOTED. POWER AND AIRSPEED WAS REDUCED AND AN UNEVENTFUL LANDING WAS MADE BACK AT THE HOME BASE. UPON INSPECTION AFTER LANDING IT WAS NOTED THAT BOTH OUTBOARD LOCKING LATCHES WERE IN THE LOCKED POSITION. THE INBOARD AFT LOCKING LATCH WAS IN THE LOCKED POSITION WITH THE COWLING SIDE LATCH COMPONENTS STILL ATTACHED. THE INBOARD FORWARD LATCH WAS NOT IN THE LOCKED POSITION AND WAS HANGING LOOSELY. THE COWLING HAS NOT BEEN RECOVERED AT THIS TIME TO DETERMINE IF THE LOCKING MECHANISM HAD FAILED.