Cessna 320 N19AS accident near Round Rock, Texas

Probable cause

Improper maintenance that led to a loss of engine power due to a failed left engine magneto, the pilot’s improper application of single engine emergency procedures, and his failure to maintain control of the airplane which resulted in a collision with trees.

NTSB analysis

The pilot departed in the multi-engine airplane and proceeded east. The airplane turned north and impacted trees about 30 nm west of the last flight track data. A postimpact fire ensued and the wreckage was destroyed.

According to a witness driving near the accident site, the airplane flew low, and she thought the airplane was going to land. Another witness driving near the accident site, observed the airplane flying “erratically” with flames emitting from the left engine, but did not remember seeing smoke in the sky or smoke emitting from the airplane. Another witness near the accident site, reported that the airplane was "sputtering" and "popping" as it flew over his home.

Postaccident examination showed that the airplane descended through trees and was highly fragmented and mostly consumed by fire. Both propellers had indications consistent with low amounts of rotational energy. The right engine propeller blades were at a blade angle near feather pitch at impact and the left engine propeller blades appeared to be fully feathered. All engine control levers were found full forward except the left engine propeller lever, which was full aft.

Additional examination revealed the right magneto installed on the left engine would not rotate due to a failed bearing. The failure signatures were indicative of a loss of lubrication in the bearing. It is likely the airplane experienced at least a partial loss of engine power in the left engine as a result. The evidence is consistent with the pilot attempting to shut down the left engine due to the failed magneto and failing to maintain single-engine flight resulting in an impact with trees and terrain.

Both engine exhaust systems were in an unairworthy condition due to very thin metal, holes, cracks, and signs of oxidative degradation. Exhaust leaks can result in an inflight fire. However, the post-impact fire prevented determination if an inflight fire occurred and the witness testimony of flames coming from the engine could not be verified.

Text from the NTSB. Open the NTSB docket for CEN20LA256 for the full record.