Beech G35 N4454D accident near Oceano, California

Probable cause

The pilot’s exceedance of the design maneuvering speed during descent in turbulence, which resulted in structural damage to the aft fuselage.

NTSB analysis

The pilot reported that, while the airplane was descending to land at an indicated airspeed of about 180 mph, it encountered turbulence for about 2 seconds. The pilot immediately reduced power and slowed the airplane to about 140 mph. The pilot continued the approach and landed the airplane without further incident. After landing, the pilot observed deformities along the fuselage.

A postaccident examination of the airplane revealed structural twisting damage to the aft fuselage, consistent with an overload failure in a tail downward direction. According to the airplane manufacturer, the damage was also consistent with damage seen on other airplanes of the same make and model that had encountered turbulence while descending at speeds higher than the airplane's design maneuvering speed. A review of the Pilot's Operating Handbook showed that the airplane's reported airspeed of 180 mph at the time it encountered the turbulence was within the caution operating range of 176 to 202 mph and was higher than the design maneuvering speed. It is likely that the pilot's exceedance of the design maneuvering speed while the airplane was descending in turbulence resulted in the structural damage to the aft fuselage.

Text from the NTSB. Open the NTSB docket for WPR12LA396 for the full record.