Aviation Accident Summaries

Aviation Accident Summary ERA21LA360

New Smyrna, FL, USA

Aircraft #1

N161AR

ZENITH 750 Cruzer

Analysis

The pilot had just purchased the experimental amateur-built airplane and performed a preflight inspection that revealed no anomalies. After departure, the elevator control became momentarily jammed in the nose-down position multiple times, and the pilot elected to return to the departure airport. After two go-around maneuvers due to elevator jamming, the elevator jammed again about 10 ft above the ground during the third landing attempt. The left wing impacted the ground and the airplane veered off the runway and came to rest inverted in a pond. Postaccident examination of the airframe revealed that the elevator bracket was becoming lodged against a nylon stop block installed in the empennage. It is likely that, while in flight, once the elevator was moved far enough in the nose-down position, the airflow around the elevator forced the elevator to contact the nylon block and jam it in the nose-down position. Examination also revealed evidence of long-term control cable contact with the empennage structure and a lack of tension on the elevator and flight control cables. A mechanic completed a condition inspection, which included examination of the flight control cables and structure, the day before the accident. Based on all available information, it is likely that this inspection was inadequate because it failed to identify and correct the flight control anomalies that ultimately resulted in the accident.

Factual Information

On September 14, 2021, about 0940 eastern daylight time, an experimental, amateur-built Zenith 750 Cruzer, N161AR, was substantially damaged when it was involved in an accident near New Smyrna Beach, Florida. The pilot and pilot-rated passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot purchased the airplane on the day of the accident and intended to fly it back to Greenville, Tennessee. He conducted a short post-purchase inspection and noted that there were no brakes or throttle control for the pilot-rated passenger in the right seat. Shortly after departing X50, he “heard a very loud boom” and the airplane “jolted nose down and to the left.” The controls were locked, and the pilot could not move the control column. The pilot applied force to the controls, and they subsequently moved, and they felt free. He then decided to return to the airport, and during a left turn onto the final approach leg of the traffic pattern, the controls intermittently locked two more times and the pilot performed a go-around. During the next approach, he heard another boom, and the controls locked again. The airplane was descending too rapidly, and the pilot performed another go-around. The pilot was able to fly the airplane back to the final approach leg of the traffic pattern without the controls locking up; however, when the airplane was about 10 ft above the runway, the controls locked again. The airplane pitched nose down and to the left and the left wing contacted the ground, followed by the nose landing gear, which collapsed. The airplane then departed the left side of the runway, impacted an embankment, and came to rest inverted in a pond. Postaccident examination of the airplane revealed that the elevator bracket was jammed on the nylon stop block, which resulted in the elevator to remain in the nose down position until force was used to move the elevator bracket off the nylon stop block. Several cycles forward and aft of the control column resulted in the elevator bracket becoming lodged on the nylon stop block each time during the examination. The nylon stop exhibited impression marks where the elevator bracket would contact it. Additionally, the rudder and elevator cables were loose, and a bungee cord was noted holding one cable up off the empennage floor. There were marks in the structure of the empennage that exhibited evidence of long-term wear due to control cable contact. The control stick could be moved several inches before cable tension and movement would occur. According to the pilot, the airplane had been retrofitted with flight controls so a handicapped individual could fly it. Prior to his purchase of the airplane, the retrofitted flight controls were removed. Review of the airplane’s maintenance logs revealed that there was no entry documenting that such maintenance had occurred. The maintenance logs also noted that the airplane’s most recent condition inspection had been completed on September 13, 2021. At that time, the airplane had accumulated 45 hours of total time in service and the mechanic certified that the airplane was inspected in accordance with 14 CFR Part 43, Appendix D and was “found to be in a condition for safe operation.”

Probable Cause and Findings

The mechanic’s inadequate inspection of the flight control system, which resulted in a loss of airplane control.

 

Source: NTSB Aviation Accident Database

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