Cessna 402C N402VN incident near San Juan, Puerto Rico

Probable cause

The airplane manufacturer’s inadequate inspection procedures, resulting in the undetected fatigue cracking of the right upper barrel and trunnion assembly.

NTSB analysis

Following the pilot’s brake application during the landing roll, an undetected fatigue crack that originated on the right upper barrel and trunnion assembly resulted in the separation of the lower portion of the landing gear. The airplane came to rest upright and the pilot and passenger successfully evacuated. A postincident inspection of the failed barrel revealed fatigue that originated on the outer surface and penetrated approximately 90 percent of the wall thickness. At the time of the incident, the operator had been performing visual inspections of the barrels looking for leaks due to cracking from the inside; the last visual inspection of the barrel was performed about 62 hours earlier. At the time of the incident, the manufacturer did not have a special inspection in place to detect fatigue cracks on the outer surface of the barrel, though there had been previous incidents and accidents in which the barrel of the upper barrel and trunnion assembly was documented to have failed due to undetected fatigue cracks that originated on the outer surface.

Text from the NTSB. Open the NTSB docket for ERA10IA384 for the full record.