Navion NAVION N1011M accident near Fort Smith, Arkansas

Probable cause

The inadequate inspection of the fuel selector valve, which was degraded, allowed fuel to leak, and resulted in fuel starvation and a loss of engine power.

NTSB analysis

Shortly after the pilot took off for a personal cross-country flight, about 300 ft above ground level, the engine lost partial power. The pilot lowered the airplane nose and the engine continued to operate, before losing total power. The pilot activated the electric fuel boost pump and engine power resumed for a few seconds. The pilot executed a forced landing to a grass area on airport property. During the forced landing, the airplane sustained substantial damage to both wings and the fuselage.

Postaccident examination of the airplane revealed blue staining on and around the fuel selector valve area, consistent with a degraded valve. The valve failed leak checks during multiple vacuum tests to check external and internal leakage, which were called for in the manufacturer’s service bulletin 106 A and related airworthiness directive (AD) 2008-05-14. No fuel was found in any fuel lines or components from the firewall forward to the engine fuel components, and about 20 gallons of fuel was recovered from the airplane fuel tanks. It is likely the degraded fuel selector valve was leaking air, which resulted in fuel starvation to the engine.

Aircraft records showed that the airplane and fuel selector valve were inspected and returned to service 2 days and about 18 flight hours before the accident. Based on the amount of fuel staining on and around the fuel selector valve and air leakage noted during the tests, the valve had likely become degraded before the last inspection. Given the valve’s degraded condition, it should have been tested and repaired or replaced during the last inspection in compliance with AD 2008-05-14.

Text from the NTSB. Open the NTSB docket for CEN20LA078 for the full record.