Amateur-built KOLB MARK N9123R accident near Collegedale, Tennessee

Probable cause

The pilot's loss of airplane control, which resulted in an aerodynamic stall. Contributing to the accident was the pilot's improper decision to take off in the nonairworthy airplane in which he had no training and his lack of flight experience in the 17 months before the accident.

NTSB analysis

The airplane's owner reported that the private pilot was supposed to be performing high-speed taxi testing of the experimental amateur-built airplane that they had just restored and built; the owner did not know that the pilot intended to take off. After two high-speed taxi tests, the owner heard the pilot apply "full power," and the airplane then lifted off the runway. A video of the takeoff showed that, after takeoff, the airplane had a high angle of attack and a steep angle of climb and that the tops of each wing were visible. The owner reported that, after takeoff, the airplane, turned right "above the trees" adjacent to the runway, and entered the traffic pattern then "leveled, banked left, and dove into the ground." A witness, who was located on the northeast end of the runway, stated that it sounded as though the pilot had reduced power before the turn but increased power during the descent and that the engine was "screaming" during the descent to ground impact. A review of the video revealed that the engine sound was smooth, continuous, and remained unchanged throughout the takeoff roll and the 45 seconds of the climb that was recorded; thus, it is unlikely that the airplane experienced an engine problem.

According to the owner, he purchased the airplane disassembled and "half restored" from what appeared to be accident damage. He and the pilot completed the repairs and assembly of the airplane using a "build manual" and a set of plans. The owner did not have airframe or engine logbooks for the airplane, and a condition inspection had not been completed. The owner said the condition inspection was supposed to have been completed "before the first flight."

The airplane kit manufacturer recommended formal training before attempting flight in the airplane make and model. The Federal Aviation Administration had also published an advisory circular (AC), which emphasized the importance of flight testing amateur-built airplanes, provided guidance on developing a plan for each phase of the amateur-built airplane's production, and suggested guidelines for the experience level of the test pilot. The guidance recommended a minimum of 40 hours of flight testing. The owner stated he was not familiar with the AC. A review of the pilot's logbook revealed that he had no training in the accident airplane make and model and that he had not logged any flight experience in the 17 months before the accident.

Given the witness statements and video evidence, it is likely the pilot lost airplane control shortly after takeoff, which resulted in an aerodynamic stall. Given that the airplane was not airworthy, that the pilot had no training in the accident make and model airplane, that the airplane had not been fully tested after it was rebuilt, and that he had no flight experience in the 17 months before the accident, the pilot should not have decided to take off in the airplane.

Text from the NTSB. Open the NTSB docket for ERA18LA134 for the full record.