What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot stated that just after takeoff, approximately 1500 feet, he heard a noise and looked to the left engine, saw that the outboard cowling on the left engine had opened, ripped away from the nacelle, and departed the aircraft in the vicinity of the privacy data omitted restaurant privacy data omitted near the north end of the air field. The pilot stated that he reduced power and then returned back to Addison Airport, landing without further incident. During the preliminary inspection, it appeared that the cowl separated and made contact with the upper side of the nacelle to wing transition area. The separated engine cowl was not recovered and could not be inspected for serviceability or damage. Maintenance records were examined and no documented engine cowling maintenance was noted during the preceding 30-days/47 flight hours. During the inspector's interview, the pilot stated that he had performed the preflight inspection on the aircraft and had opened the engine cowl to check the oil and inspect the engine bay, and then closed and latched the cowl. Normal design and operation of the engine cowl is as follows; the cowl is a clamshell type, piano hinged at the top and secured at the bottom by two (forward and aft) latches; the cowl has latch receptables that seat over the eye of rod-end type bolts that are attached to the structure of the nacelle (forward and aft). Each latch has a slide mechanism that slides a bar thru the eye of the rod end. From the fully closed and seated position, the latches are fully recessed (flush) into the cowl, securing the cowl to the nacelle structure. When not fully latched, the latches protrude above the surface of the cowl. Inspection of the engine nacelle revealed the following; the hinged portion of the cowl was partially intact and had visible signs of separation along the hinge tabs with evidence of bending, twisting, and ductile overload failure consistent with failure in an aft direction. The hinge pin remained intact. The forward nacelle mounted rod end was intact and showed evidence of moderate chafing. The aft nacelle mounted rod end was intact and showed evidence of minor chafing. Neither rod end showed visible signs of bending, twisting, malformation, or related ductile overload failure.
As the FAA filed it
THE PILOT STATED THAT JUST AFTER TAKEOFF, APPROXIMATELY 1500 FEET, HE HEARD A NOISE AND LOOKED TO THE LEFT ENGINE, SAW THAT THE OUTBOARD COWLING ON THE LEFT ENGINE HAD OPENED, RIPPED AWAY FROM THE NACELLE, AND DEPARTED THE AIRCRAFT IN THE VICINITY OF THE ^PRIVACY DATA OMITTED^ RESTAURANT ^PRIVACY DATA OMITTED^ NEAR THE NORTH END OF THE AIR FIELD. THE PILOT STATED THAT HE REDUCED POWER AND THEN RETURNED BACK TO ADDISON AIRPORT, LANDING WITHOUT FURTHER INCIDENT. DURING THE PRELIMINARY INSPECTION, IT APPEARED THAT THE COWL SEPARATED AND MADE CONTACT WITH THE UPPER SIDE OF THE NACELLE TO WING TRANSITION AREA. THE SEPARATED ENGINE COWL WAS NOT RECOVERED AND COULD NOT BE INSPECTED FOR SERVICEABILITY OR DAMAGE. MAINTENANCE RECORDS WERE EXAMINED AND NO DOCUMENTED ENGINE COWLING MAINTENANCE WAS NOTED DURING THE PRECEDING 30-DAYS/47 FLIGHT HOURS. DURING THE INSPECTOR'S INTERVIEW, THE PILOT STATED THAT HE HAD PERFORMED THE PREFLIGHT INSPECTION ON THE AIRCRAFT AND HAD OPENED THE ENGINE COWL TO CHECK THE OIL AND INSPECT THE ENGINE BAY, AND THEN CLOSED AND LATCHED THE COWL. NORMAL DESIGN AND OPERATION OF THE ENGINE COWL IS AS FOLLOWS; THE COWL IS A CLAMSHELL TYPE, PIANO HINGED AT THE TOP AND SECURED AT THE BOTTOM BY TWO (FORWARD AND AFT) LATCHES; THE COWL HAS LATCH RECEPTABLES THAT SEAT OVER THE EYE OF ROD-END TYPE BOLTS THAT ARE ATTACHED TO THE STRUCTURE OF THE NACELLE (FORWARD AND AFT). EACH LATCH HAS A SLIDE MECHANISM THAT SLIDES A BAR THRU THE EYE OF THE ROD END. FROM THE FULLY CLOSED AND SEATED POSITION, THE LATCHES ARE FULLY RECESSED (FLUSH) INTO THE COWL, SECURING THE COWL TO THE NACELLE STRUCTURE. WHEN NOT FULLY LATCHED, THE LATCHES PROTRUDE ABOVE THE SURFACE OF THE COWL. INSPECTION OF THE ENGINE NACELLE REVEALED THE FOLLOWING; THE HINGED PORTION OF THE COWL WAS PARTIALLY INTACT AND HAD VISIBLE SIGNS OF SEPARATION ALONG THE HINGE TABS WITH EVIDENCE OF BENDING, TWISTING, AND DUCTILE OVERLOAD FAILURE CONSISTENT WITH FAILURE IN AN AFT DIRECTION. THE HINGE PIN REMAINED INTACT. THE FORWARD NACELLE MOUNTED ROD END WAS INTACT AND SHOWED EVIDENCE OF MODERATE CHAFING. THE AFT NACELLE MOUNTED ROD END WAS INTACT AND SHOWED EVIDENCE OF MINOR CHAFING. NEITHER ROD END SHOWED VISIBLE SIGNS OF BENDING, TWISTING, MALFORMATION, OR RELATED DUCTILE OVERLOAD FAILURE.