Amateur-built CCX-2000 N10TA accident near Hood River, Oregon

Probable cause

The total loss of engine power due to improper construction of the muffler, which resulted in separation of the internal components.

NTSB analysis

The experimental, amateur-built airplane was retrofitted with an experimental exhaust system that comprised a titanium exhaust header and aluminum muffler.

On the first flight with the new exhaust system, the engine lost total power just after takeoff. The pilot performed a forced landing during which the airplane impacted trees, resulting in substantial damage.

Examination of the engine revealed that the muffler inner tube failed due to creep fatigue and fractured into several fragments. Components of the muffler included a perforated inner tube, surrounded by fiberglass packing material held in place by five clamps; an outer shell; end caps; and an inlet and exhaust tube, all constructed out of 6061-T6, an aluminum alloy not suited for use above 350°F to 400°F. Any use near or above that temperature will cause additional heat treatment and changes to the properties and performance of the material. The observation of the creep separation indicates that the material was exposed to much higher temperatures than this, likely between 600°F and 1000°F. It is likely that, when exposed to the hot exhaust gasses during takeoff, the fragments, clamps, and fiberglass packing material migrated aft and collapsed the remaining section of the inner tube, which plugged the exhaust port and resulted in a total loss of power. A postaccident test run of the engine without the muffler revealed no anomalies.

Text from the NTSB. Open the NTSB docket for WPR21LA250 for the full record.