ZENITH Zodiac CH601

Full Narrative

On December 8, 2024, about 1210 central standard time, an experimental Zenith Zodiac CH601 airplane, N9853M, was destroyed when it was involved in an accident near Columbia, Illinois. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight.
The pilot reported that he had changed the oil pressure sender due to faulty readings, and the accident flight was a post-maintenance test flight. Shortly after takeoff, he observed smoke in the cockpit and smelled burning oil. The engine lost total power and the cabin filled with smoke. He opened the airplane’s canopy in an attempt to dissipate the smoke, but then discovered that he was unable to control the airplane. The airplane impacted the ground and was subsequently consumed by a postimpact fire.
The accident site was located in a flat agricultural field about 0.3 nautical miles from the airport. Video from a nearby surveillance camera showed the airplane impact the field in a nose-high, wings-level attitude, nose over, and come to rest inverted, with smoke immediately visible. The pilot stated that he used an onboard fire extinguisher until two witnesses arrived and pulled him from the airplane. The engine compartment, forward fuselage, and cockpit were fully engulfed by fire when first responders arrived.
The debris path extended about 61 ft on a heading about 139° to the main wreckage. The engine compartment, fuselage, and inboard sections of both wings had extensive thermal damage from a post-crash fire. Flight control continuity from the control surfaces to the cockpit was confirmed, along with the engine power control. The cockpit controls were destroyed during the post-crash fire.
The engine was an experimental, inline-four-cylinder, normally aspirated engine. Postaccident examination revealed damage consisting of several holes in the engine case and oil pan that corresponded with a damaged piston assembly, along with thermal damage of the oil pan and case.
The No. 3 cylinder connecting rod was found in the debris field. The connecting rod journal was observed to be black and wiped consistent with oil starvation. The oil filter was found to be ¼ turn from fully loose and was easily rotated and removed by hand.
A review of the engine maintenance logbook did not reveal any entries related to the pilot’s replacement of the oil pressure sender. The pilot’s hangar contained a used oil drain pan, with wet oil still inside, as well as a 5-gallon bucket of used engine oil next to an open toolbox.