CHARTER FLT HAS LOUD BANG; VIBRATION; AND YAW; BUT ENG NORMAL. DETERMINE IT IS COWL SEPARATION. SHUT DOWN ENG; RETURN LAND.

Narrative

WHILE CLBING ENRTE THROUGH FL180 WE EXPERIENCED A LOUD BANG FROM THE R REAR OF THE ACFT; WITH ENSUING VIBRATION; AND YAW TO THE R. WITH ENG INDICATIONS AND SYS INDICATING NORMAL; I DETERMINED THE PROB TO BE AN OPEN #2 ENG COWL. THE LARGE AMOUNT OF DRAG PRODUCED; COUPLED WITH ENG AND AIRFRAME ANTI-ICE ON THE #1 ENG; AS I ELECTED TOO SHUT DOWN AND SECURE THE #2 ENG; REQUIRED ALMOST FULL TRIM FOR RUDDER AND AILERON INTO THE GOOD ENG. WE NOTIFIED CLEVELAND CTR OF OUR INTENTIONS TO RETURN TO WILLOW RUN ARPT AND THE REASONS FOR DOING SO. UPON LANDING AT THE ARPT; TWR CONFIRMED OUR SUSPICIONS; AND STATED THE #2 COWL WAS OPEN AND MISSING THE BOTTOM PORTION. AS WE SHUTDOWN THE ENG AND SECURED THE ACFT WE INSPECTED THE #2 ENG. THE BOTTOM OUTBOARD COWL DOOR SEPARATED IN FLT AND THE TOP PORTION WAS WEDGED UPWARD AND BACK INTO THE REAR PORTION OF THE COWL. THE MISSING PORTION OF THE COWL APPEARS TO HAVE FALLEN INTO LAKE ERIE. AT THIS TIME; I BELIEVE THAT THE ENG COWL MAY HAVE APPEARED FULLY LATCHED TO THE MECHS ON THEIR TRANSIT INSPECTION. I HAVE SEEN INSTANCES WHERE THE BOTTOM LATCH APPEARS CLOSED BUT THE INTERIOR HOOK ON THE LATCH DOES NOT ENGAGE. IN MY PREFLT OF THE ACFT I DISCOVERED NOTHING UNSAFE OR OUT OF THE ORDINARY. THERE WERE MECHS AT THE ACFT FOR THE BEFORE START; ALL CLR TO START; AND TO TAXI PORTION OF THE BEGINNING OF THE TRIP. I BELIEVE THE DECISION TO SHUTDOWN THE R ENG PREVENTED FURTHER DAMAGE AND NORMAL USE OF CHKLISTS CONTRIBUTED TO THE UNEVENTFUL LNDG. I BELIEVE THE PRESSURE TO QUICK TURN AN ACFT BY COMPANY PERSONNEL MAY HAVE PUT THE MECHS UNDER INCREASED STRESS. THE TRUST THE CREW HAS IN MAINT MUST BE RELIABLE OR THERE IS NO REASON TO HAVE A MECH AT AN ACFT AFTER THE CREW HAS CONDUCTED A PREFLT. WE PERFORMED WHEN THE PROB AROSE AS WE WERE TRAINED TO DO; AND PREVENTED FURTHER DAMAGE.