Amateur-built RV-4 N416DH accident near Carthage, North Carolina

Probable cause

A partial loss of engine power for reasons that could not be determined because postaccident examinations of the engine and fuel system revealed no anomalies that would have precluded normal operation. Contributing to the severity of the accident was the rear-seat pilots' decision to abort the landing with partial engine power and his failure to successfully perform a forced landing to an available airfield.

NTSB analysis

During cruise flight, the engine began losing power. The pilot in the front seat, who was flying the airplane, attempted to troubleshoot the engine issue, including activating the carburetor heat; however, the engine continued to run roughly, so he chose to divert to a nearby airport. The rear-seat pilot then took control of the airplane. While on final approach to the runway, the rear-seat pilot asked the front-seat pilot, who was seated near the wing flap control, to configure the flaps for landing. After the flaps fully extended, they retracted. The rear-seat pilot then asked the front-seat pilot to re-extend the flaps. About this time, the rear-seat pilot noticed that people and vehicles were at the end of the runway and chose to abort the landing by increasing engine power and turning the airplane toward an adjacent field. However, the airplane had sufficient altitude and power, so the pilot should have been able to make the runway and land safely. During the subsequent attempt to land the airplane, it stalled and then touched down hard. The airplane was substantially damaged, and both pilots were seriously injured.

Postaccident examination of the airplane revealed that the wing flaps appeared to be fully extended. The front-seat pilot, who was a co-owner, had been working to rectify several maintenance discrepancies he had identified after purchasing the airplane 2 months earlier, one of which included a leaking right fuel tank; he had repaired the exterior of the tank. Examination of the engine and fuel system identified the presence of fuel tank sealant on the exterior of the steel braid of both fuel tanks' flexible pick-up tubes and flaked pieces of fuel tank sealant and other contaminants within the gascolator. However, examinations revealed that the fuel screens at the engine-driven fuel pump and the carburetor were not contaminated. Both fuel tanks were found breached. An examination of the engine did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation. Although the temperature and dew point about the time of the accident were conducive to the formation of carburetor ice, it unlikely that carburetor ice played a role in the loss of engine power because the pilots' reported using carburetor heat following the loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA13LA072 for the full record.