ERA17FA317

The pilot's early entry into and failure to maintain rotor rpm during a forced landing autorotation after performing an engine shutdown in flight, which resulted in an uncontrolled descent. Contributing to the accident was the failure of maintenance personnel to properly rig the throttle control tie-rod assembly, which resulted in an in-flight separation of the assembly and rendered control of engine rpm impossible.

The purpose of the flight was to provide an orientation/pleasure flight to the passenger, who was scheduled to perform in a concert on the airport later that evening. Several minutes after takeoff, the pilot reported over the airport UNICOM frequency that he was unable to control engine rpm with throttle inputs. He reported that he could "roll" the twist-grip; however, there was no corresponding change in engine power when he did so. Three helicopter flight instructors, one a Federal Aviation Administration (FAA) inspector, one an FAA designated examiner, and a company flight instructor, joined the conversation on the radio to discuss with the pilot remedial actions and landing options. These options included a shallow, power-on approach to a run-on landing, or a power-off, autorotational descent to landing. The instructors encouraged the pilot to perform the run-on landing, but the pilot reported that a previous run-on landing attempt was unsuccessful. He then announced that he would shut down the engine and perform an autorotation, which he said was a familiar procedure that he had performed numerous times in the past. The instructors stressed to the pilot multiple times that he should delay the engine shutdown and autorotation entry until the helicopter was over the runway surface. Video footage from a vantage point nearly abeam the approach end of the runway showed the helicopter about 1/4 to 1/2 mile south of the runway as it entered a descent profile consistent with an autorotation. Toward the end of the video, the descent profile steepened and the rate of descent increased before the helicopter descended out of view. Witnesses reported seeing individual rotor blades as the main rotor turned during the latter portion of the descent. The increased angle and rate of descent and slowing of the rotor blades is consistent with a loss of rotor rpm during the autorotation. Despite multiple suggestions from other helicopter instructors that he initiate the autorotation above the runway, the pilot shut down the engine and entered the autorotation from an altitude about 950 ft above ground level between 1/4 and 1/2 mile from the end of the runway. Upon realizing that the helicopter would not reach the runway, the pilot could have landed straight ahead and touched down prior to the runway or performed a 180° turn to a field directly behind the helicopter; however, he continued the approach to the runway and attempted to extend the helicopter's glide by increasing collective pitch, an action that resulted in a decay of rotor rpm and an uncontrolled descent. Examination of the wreckage revealed evidence consistent with the two-piece throttle control tie rod assembly having disconnected in flight. The internally threaded rod attached to the bellcrank and an externally threaded rod-end bearing attached to the throttle control arm displayed damage to the three end-threads of each. The damage was consistent with an incorrectly adjusted throttle control tie rod assembly with reduced thread engagement, which led to separation of the rod end bearing from the tie rod and resulted in loss of control of engine rpm via the throttle twist grip control.

HISTORY OF FLIGHT On September 8, 2017, about 1300 eastern daylight time, a Schweizer 269C-1 helicopter, N204HF, was substantially damaged during a collision with terrain while performing a forced landing to runway 01 at Flying W Airport (N14), Medford, New Jersey. The commercial pilot and passenger were fatally injured. The helicopter was owned by Herlihy Helicopters Inc and operated by Helicopter Flight Services under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. According to the chief flight instructor for the operator, the purpose of the flight was to provide an orientation/pleasure flight to the passenger, who was scheduled to perform in a concert on the airport later that evening. Several minutes after takeoff, the pilot reported over the airport UNICOM frequency that he was unable to control engine rpm with throttle inputs. He reported that he could "roll" the twist-grip but that there was no corresponding change in engine rpm when he did so. The company flight instructor and another helicopter flight instructor, who was a designated pilot examiner (DPE), were monitoring the frequency and engaged the pilot in conversation about potential courses of action to accomplish a landing. A Federal Aviation Administration (FAA) inspector, who was also a helicopter instructor and examiner, joined the conversation on the radio. Options discussed included a shallow approach to a run-on landing or a power-off, autorotational descent to landing. The instructors suggested that the pilot perform the run-on landing; however, the pilot reported that a previous attempt to perform a run-on landing was unsuccessful and announced that he would stop the engine and perform a power-off autorotation. The pilot stated that this was a familiar procedure he had performed numerous times in the past. When asked over the radio by the DPE when he had last performed an autorotation to touchdown, the pilot replied that 4 months had elapsed since his most recent touchdown autorotation. Subsequent attempts to convince the pilot to attempt a run-on landing were unsuccessful. According to the DPE and the FAA inspector, the pilot was advised "multiple times" to aim to touch down "midfield" and not to initiate the engine shutdown and autorotation until over the runway. According to the DPE, his last reminder to the pilot came when the helicopter was on a 2-mile final approach. A video forwarded to the NTSB by local police was recorded from a vantage point nearly abeam the approach end of runway 01. The video showed the helicopter about 1/4 mile south of the runway as it entered a descent profile consistent with an autorotation. Toward the end of the video, the descent profile became more vertical, and the rate of descent increased before the helicopter descended out of view. No sound could be heard from the helicopter. During a postaccident interview with law enforcement, the company flight instructor reported that the helicopter entered the autorotation about 950 ft above ground level (agl) and that the helicopter was quiet during its descent "because the engine was off." During the descent, the rotor rpm decayed to the point where the instructor could see the individual rotor blades. The helicopter descended from view before reaching the runway threshold, and the sounds of impact were heard. Both the instructor and the FAA inspector reported that a high-pitched "whine" could be heard from the helicopter during the latter portion of the descent. In a written statement, the flight instructor reported, "[the pilot] began the autorotative descent, but it was not long before it became apparent it was not being executed correctly. I began to see individual blades instead of a translucent disc. His vertical speed increased while his horizontal speed became almost non-existent. The nose of the [helicopter] rolled forward. Instead of being able to see the bottom of the [helicopter]… all I could see was the cockpit glass and rotor head." PERSONNEL INFORMATION The pilot held commercial and flight instructor certificates, each with ratings for rotorcraft-helicopter and instrument helicopter. His most recent FAA second-class medical certificate was issued April 12, 2017. Excerpts of the pilot's logbook revealed that he had logged 480.9 total hours of flight experience, of which about 300 hours were in the accident helicopter make and model. The last entry logged was for 1.2 hours in the accident helicopter on the day of the accident. Company training records indicated that the pilot had received the training required by the operator for employment as a flight instructor, and his last airman competency check was completed satisfactorily on April 19, 2017, in the accident helicopter. AIRCRAFT INFORMATION The helicopter was a single-engine, two-seat, light utility helicopter constructed primarily of aluminum alloy and powered by an air-cooled, Lycoming HO-360-C1A, 180-horsepower engine. It was equipped with conventional collective and cyclic control sticks and tail rotor control pedals. The main rotor was a fully articulated, three-bladed design, and the tail rotor was a two-bladed, semi-rigid, anti-torque rotor design. Power was transmitted from the engine to the rotor system through a V-belt drive, which incorporated a free-wheeling (one-way) sprag clutch, a main drive transmission, a tail rotor transmission, and shafts. According to FAA records, the helicopter was manufactured in 2000, delivered to the owner/operator, and had accrued about 7,899 total aircraft hours. Its most recent 100-hour inspection was completed on August 17, 2017, at 7,884 total aircraft hours. A review of maintenance records revealed that the helicopter's engine was replaced with factory rebuilt or overhauled engines at the manufacturer's recommended overhaul intervals. Engine changes occurred in 2003, 2006, and most recently, on September 24, 2011. The records reflected numerous entries regarding carburetor discrepancies. Carburetors were adjusted or removed and replaced with loaner carburetors then reinstalled following repairs. In February 2014, the carburetor was removed, sent out for repair, and reinstalled by the operator. On August 31, 2016, the operator installed a throttle control cable manufactured by McFarlane Aviation Products, as documented on an FAA Form 337. A cable from the original equipment manufacturer was not available per the operator, and the FAA approved the manufacture and installation, which required the cable's inspection at 25-hour intervals. The inspections were documented; the most recent was completed concurrent with the annual inspection conducted 15 hours before the accident. The operator was interviewed during a meeting with NTSB investigators and FAA inspectors regarding the maintenance history of the accident helicopter. He was later interviewed by telephone to gain more detail about the disassembly/reassembly and rigging of the throttle during carburetor/engine changes. According to the operator, when the engine was changed for overhaul, the carburetor traveled with the engine, and the throttle control arm was removed at the carburetor splined shaft. The throttle control bellcrank was removed from the front of the carburetor, and the entire throttle control system remained with the helicopter. The throttle control arm, the throttle tie rod, the throttle control bellcrank, and the throttle cable all remained attached to each other and to the helicopter. He stated that, because of this, there was no need to disconnect or adjust the throttle tie rod that connected the bellcrank and the throttle control arm. He also stated that, when a new engine was installed, the correct "angle" was measured for the installation of the throttle control arm on the carburetor. Adjustment of idle and mixture set screw