NTSB Final Report: Cosby, TN

Aircraft:                                     ROBINSON HELICOPTER COMPANY R44 II

Aircraft Damage:             Substantial

Analysis

The pilot was preparing for a cross-country flight in the newly-leased, non-instrument flight rules (IFR) equipped helicopter. Per the lease agreement, he flew in the local traffic pattern to assess the helicopter without incident. The weather reportedly deteriorated during the day, changing from marginal visual flight rules (VFR) conditions to IFR conditions. Local personnel warned him of the hazards of flying through the Smoky Mountains in such conditions; however, the pilot responded, “those are hills” and he had 14 years of mountain flying experience. The pilot subsequently took off with his passenger toward mountainous terrain.

On-board video captured most of the flight and all of the accident sequence, revealing that the pilot proceeded to the east, flying along valleys and roads, as the mountains ahead were obscured in low ceilings. The flight continued as the visibility eventually deteriorated to “zero” and the helicopter entered instrument meteorological conditions. The were no attempts to reverse course to get to better weather. The pilot eventually lost control of the helicopter and crashed into a tree line in a steep descent. The helicopter was substantially damaged, the pilot was seriously injured, and his passenger was fatally injured. The pilot would later report to law enforcement personnel that he remembered losing engine oil pressure and the main rotor began to make a loud noise, so he performed an autorotation; however, with the cloud cover, he could not see.

Postaccident examination of the airframe and engine revealed no evidence of a malfunction or anomaly that would have precluded normal operation. There was no evidence of a loss of engine oil or oil pressure. The on-board video did not support the pilot’s claims of an inflight loss of oil pressure or a main rotor malfunction, nor did it indicate that an autorotation was performed.

Findings

History of Flight

On December 29, 2021, at 1425 eastern standard time, a Robinson Helicopter Company R-44 II, N544SC, was substantially damaged when it was involved in an accident near Cosby, Tennessee. The commercial pilot received serious injuries and the passenger was fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to personnel at Gatlinburg-Pigeon Forge Airport (GKT), Sevierville, Tennessee, the pilot and passenger traveled from Utah to pick up the helicopter after leasing it from the owner. They arrived at the service center where the helicopter had been stored about 0830 on the day of the accident. The pilot reviewed the lease agreement and conducted a local flight around the GKT airport traffic pattern to assess the helicopter per the lease agreement.

 According to personnel at the service center, “the weather throughout the day was changing from marginal VFR conditions to IFR conditions.” The pilot had conversations with the service center employees about leaving the area but was cautioned by all of them he spoke with about the dangers of flying in the Smoky Mountains in marginal weather. One person showed him a book in their training room filled with controlled flight into terrain (CFIT) accidents that occurred in the area. The pilot’s response was “those are hills,” and informed him he had 14 years of experience of mountain flying. Additionally, a local helicopter air ambulance pilot who worked on the airport met the pilot and asked about his intentions. The pilot stated he planned on departing towards Asheville and was going to follow Interstate 40 (I-40) through the gorge to Raleigh, North Carolina, where he would visit relatives before heading back west. The other helicopter pilot told him that the mountains east of GKT were 6,000 ft and “there was no way he would make it there.” He also stated there were powerlines above the I-40 gorge.

 About 1413, the pilot and passenger departed GKT eastbound. Federal Aviation Administration radar data showed the helicopter flying through the valleys in an easterly/southeasterly direction at altitudes between 1,200 ft and 1,750 ft. The data was not continuous along the route.

 A GoPro video camera was mounted inside the cockpit and was recording during the flight. The camera and its memory card were forwarded to the National Transportation Safety Board Vehicle Recorders Laboratory for examination and analysis.

As the helicopter approached an area of low visibility and rising terrain, the helicopter continued in a gradual ascent. At 1424:34, the visibility started to greatly decrease. The helicopter’s groundspeed (and indicated airspeed) at first showed a decreasing trend. By 1424:48, the manifold pressure was reduced and the groundspeed and indicated airspeed decreased and reached a minimum of less than 20 knots.

As the indicated airspeed reached a minimum, manifold pressure increased, the helicopter pitched forward, and airspeed increased slightly. Visible landmarks under the helicopter suggested it again had a forward component of speed. As the helicopter continued to fly forward, visibility decreased even further, eventually to “zero” at 1425:07. About the time this occurred, the manifold pressure went through the red arc range to a maximum of about 27 inHg (beyond the red arc range). The helicopter then pitched forward and airspeed rapidly increased to about 85 knots. During this time, the manifold pressure indicated steadily above the red arc (above 27 inHg). The helicopter then appeared to yaw rapidly to the right, the airspeed suddenly displayed “zero” knots, and the altitude decreased. The low rotor rpm warning light and aural warning alerted.

The helicopter emerged from the cloud layer, first in a right roll and right yaw condition that quickly reversed to a left roll and left yaw condition. The helicopter then descended rapidly into a tree line, impacting the tops of the trees in a left yaw and level roll condition. As the helicopter descended into the tree line, the main rotor blades struck tree branches and tree trunks. Reflections in the windshield suggested the low rotor rpm light (yellow), and the low engine oil pressure light (red) illuminated during impact. The helicopter came to rest amongst the trees at ground level.

There was no evidence in the recording that suggested that there were preimpact mechanical malfunctions or failures that would have precluded normal operation prior to the helicopter entering an extremely low visibility condition.

Local law enforcement personnel interviewed the pilot after the accident. He stated that he did recall the accident. He further stated that he remembered losing oil pressure and the main rotor began to make a loud noise, so he performed an autorotation; however, with the cloud cover, he could not see.

Pilot Information

The pilot’s total flight experience was obtained from his latest Federal Aviation Administration first-class medical certificate application, dated 12/7/2021. A pilot logbook was found in the wreckage; however, it was water-damaged and partially illegible and a total flight time could not be determined.

The helicopter was not certificated for flight in instrument meteorological conditions.

Meteorological Information and Flight Plan

Airport Information

Wreckage and Impact Information

The helicopter came to rest on a heading of 210°, on steep, wooded terrain. There was no fire. The cabin impacted the ground and was crushed forward with the tail boom raised behind the cabin. The tail rotor was separated and resting on the right side of the wreckage. Examination of the wreckage revealed all airframe, main rotor, tail rotor, and powerplant components were accounted for at the scene. The main and auxiliary fuel tanks remained attached to the fuselage. The auxiliary fuel tank was examined and appeared to be full. Fuel was collected from both tanks with no contamination noted. Flight control continuity was confirmed from all flight control surfaces to the flight controls in the cockpit.

The engine was examined and remained attached to the airframe with minor impact damage. The engine compartment was free of oil or fuel residue; there was no evidence of a loss of engine oil in flight.

Both main rotor blades remained attached to the main rotor hub, and one blade was bent, but complete. The other blade was bent and impact-separated into three pieces. The majority of the blade was attached to the main rotor hub, with 3 ft of the tip separated in two sections: about 2.5 ft of blade material and the weighted tip. Both sections were located near the main wreckage to the north.

After recovery of the wreckage to a salvage storage facility, the engine was examined in greater detail. The engine mount and structural tubing aft of the firewall were impact damaged. The engine-driven fuel pump overboard drain line fitting was impact-separated from the pump. The fuel strainer was impact damaged. The fuel strainer screen was absent of debris.