Hawker Beechcraft CORP 400A accident near Charleston, South Carolina, September 14, 2021

The NTSB's narrative final · quoted from the NTSB record

The flight crew initiated a positioning flight following major maintenance, which included the removal and re-installation of both engine cowlings. The flight was uneventful until about 15 minutes from the destination. While descending, a sudden bang and yaw occurred. There were no annunciations or other warnings observed before or after the event, and the airplane remained controllable. The flight crew continued to the destination and landed without further incident. On the ground, it was discovered that the entirety of the left engine’s four-panel cowling had separated in flight and impacted the rear fuselage and horizontal stabilizer resulting in substantial damage. Further examination of the left engine area revealed that several cowling fasteners were missing from the receptacles. During maintenance immediately preceding the flight, the left cowling fasteners had to be removed a second time due to an alignment issue with the panels. The mechanic who performed the work reported that the misalignment was resolved, and the fasteners were tightened. A second mechanic visually inspected the work and did not notice any abnormalities, nor did the pilots during their preflight inspection. It is likely that several fasteners departed the left cowling during this first flight after maintenance, which resulted in a rapid departure of the cowling panels. Given that none of the cowling was recovered, the initiating factors that would lead to the separation could not be determined. Denting and rippling were discovered on the right cowling; however, the investigation was unable to determine when the damage was incurred as it was not discovered until about 1 month after the accident. The mechanics and flight crew did not recall observing any damage to either cowling before flight.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

Photographs from the investigation 13 pictures from the NTSB's docket, as the NTSB released them

Photo 1 – View of the accident airplanePhoto 2 – View of the left engine with the separated cowlingPhoto 3 – View of the damaged horizontal stabilizerPhoto 4 – View of the damaged left side of the fuselagePhoto 5 – View of the rear top portion of the left engine areaPhoto 6 – View of the left side of the left enginePhoto 7 – View of the left engine inboard aft areaPhoto 8 – View of the aft left engine areaPhoto 9 – View of the left engine forward areaPhoto 10 – View of the aft left engine areaPhoto 11 – View of the forward left engine areaPhoto 12 – View of the right engine top inboard cowling. Note rippling and dent areas.Photo 13 – Additional view of the right engine cowling top and leading-edge area.

The NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.