20211010019409A

On October 10, 2021, at 1357 local time, a Robinson R44 ii, N637HP, was destroyed when it was involved in an accident in Cornwall, new york. The pilot was fatally injured. The helicopter was operated as a part 91 personal flight.

According to fueling records, the pilot purchased 24.6 gallons of fuel prior to departure from floyd bennet memorial airport (gfl), glenn falls, new york, about 1247. The destination was macarthur airport (isp), ronkonkoma, new york, where the helicopter was based.

According to FAA tracking data, at 1356, as the helicopter was flying southbound over the center of the hudson river at an altitude of about 1,700 ft MSL it began a climbing right turn toward the west. As it reached the shoreline, it turned right again and flew toward the northwest for about 1/4 mile, before it descended and turned left about 90°. The recorded data ended about 120 yards north of the accident site. The entire flight was about 70 minutes and the accident site was located about 120 nautical miles south of gfl.

A witness located on a hiking trail about 0.1 mile southeast of the accident site reported hearing the helicopter?s engine "falter and die." One to two seconds later, he heard a swishing sound, which he attributed to the helicopter "spinning" or being ?out of control,? However he could not see the helicopter due to the tree canopy. Shortly thereafter, he heard a series of loud noises that he described as "backfires, at machine gun speed? For about 2 seconds, which he surmised was ?the engine catching and the rotors slapping," and then the sounds stopped. He reported that the visibility was "clear," the clouds were higher than the mountain peaks, there was no fog over the river, and he could see the river clearly from his location on the hiking trail.

A second witness located about 1/2-mile northwest of the accident site reported hearing a "loud noise" that he believed was the helicopter?s engine. When he turned toward the noise, he observed the helicopter in a nose down attitude of nearly 90°, travelling at a "high speed?straight down." The witness lost sight of the helicopter as it descended below a tree line; shortly thereafter he "heard it crash."

Examination of the accident scene revealed a debris path that was about 150 ft long and oriented on a heading of about 188° magnetic. It began with damaged treetops and broken limbs, where the tail rotor assembly and tail rotor guard were located. The main impact crater was about 60 ft from the initial tree strike, with the main wreckage located about 60 ft beyond the crater. The fuselage was fragmented and compressed from the nose toward the rear seats. All flight control fittings remained attached at their ends. The push-pull tubes between the servos and the swashplate remained intact. All other push-pull tubes were fractured, some in multiple locations, consistent with overload. The sprag clutch operated normally when rotated by hand. All drive belts were intact and found in place. The fuel tanks were impact damaged; their bladders were breached, and a trace amount of fuel remained in the bladders. Some vegetation surrounding the crater and the main wreckage showed evidence of fuel blight. Both magnetos were separated from the engine. The left magneto was fractured and the lower half was not recovered. The right magneto had some impact damage to the top near the condenser but was otherwise intact. It would not produce a spark on any leads when tested.

The 1345 weather conditions at stewart airport (swf), located 7 miles northwest of the accident site at an elevation of 491 ft MSL, included an overcast ceiling at 1,500 ft, visibility 5 miles in mist. At the time of the accident an advisory was in effect for the area and the intended destination, warning of possible instrument flight rules weather conditions.

The helicopter was retained by the NTSB for further examination. This report will be amended if further information becomes available.