Amateur-built Cavalon accident near Sebring, Florida, October 30, 2018

The NTSB's narrative final · quoted from the NTSB record

On the morning of the accident, the commercial pilot flew the accident gyroplane for 2 hours and then serviced it with fuel. Later that day, he departed on the accident flight with the passenger. Radar information revealed that the accident gyroplane climbed to an altitude of about 1,000 ft and began a cruise profile on a westerly heading. The gyroplane's radar track traversed the southern border of a nearby lake until it began to descend while flying over the southwestern shore of the lake. The gyroplane's descent followed the shoreline to the northwest before the radar target disappeared. At that point, the gyroplane was at an altitude of 900 ft, a groundspeed of 90 knots, and was located about 0.4 mile southeast of the accident site. Two mayday calls from the gyroplane were recorded before the sound of impact. During the audible portions of the transmissions, sounds consistent with increasing and decreasing engine power were heard. One witness observed the gyroplane when it was about 300 ft above ground level "with very little airspeed" and before it "entered an autorotation." The witness described multiple heading changes before the gyroplane descended from his view. The gyroplane collided with power lines, a power pole, and a residence. The gyroplane and the residence were consumed by postcrash fire. Examination of the wreckage revealed the pitch control cable between the cyclic control tube and the main rotor head had likely disconnected at the control tube during flight. This connection was secured by a bolt and nut, which were not recovered. The pilot took possession of the gyroplane on the day before the accident. Upon inspection, the pilot found improper logbook documentation and learned of mechanical discrepancies, including the need for a rotor balance, that rendered the gyroplane unairworthy, but he flew it anyway. During the subsequent flight, the pilot noted that the cyclic pitch control vibration was "excessive." After landing, the pilot attempted to bring the rotor system into balance, but the rotor vibration persisted. The continuing vibration was an indication of a safety-of-flight issue, yet the pilot continued to fly the gyroplane. Given this information, it is likely that the disconnection of the cyclic pitch control tube from the main rotor system was due to the separation of a bolt and nut that connected them together. Because the nut and bolt were not recovered, they could not be examined to determine whether they had been assembled correctly. While it could not be definitively determined why the nut and bolt separated, it is likely that the unabated vibration reported by the pilot during the previous flights contributed to their eventual separation, and the inflight loss of pitch control. Despite this, the gyroplane likely was still controllable through the use of electric/pneumatic trim and engine power application, per a published emergency procedure. Given the witness statements describing the final moments of the flight, it is likely that the pilot lost control of the gyroplane before impacting powerlines and a residence.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.