NTSB Factual Report

HISTORY OF FLIGHT

On September 28, 2014, about 1520 central daylight time, an experimental amateur-built Eagle R & D Helicycle helicopter, N7062U, impacted terrain after a loss of control while maneuvering in Gallatin, Tennessee. The private pilot was fatally injured and the helicopter was substantially damaged. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations (CFR) Part 91. The flight departed from a private residence about 1519 and was destined for Sumner County Regional Airport (M33), Gallatin, Tennessee.

According to a friend of the pilot, the pilot had departed M33 earlier in the day and flown to the friend's property. The landing was uneventful, and, while the pilot was there, he borrowed some tools and increased the tension on the helicopter's drive belts. According to the friend, about 1519, the pilot started the helicopter, lifted off, and departed to the southwest. The friend assumed that the pilot was heading back to M33, but, about 1 minute later, he observed the helicopter flying toward him in a nose-low attitude, about 400 ft above ground level, and at a "high rate of speed." The helicopter then suddenly pitched over, began to tumble, and impacted in an inverted attitude, and a postcrash fire ensued.

PERSONNEL INFORMATION

Federal Aviation Administration (FAA) and Pilot Records

According to FAA records, the pilot was first certificated in 1973 and held a private pilot certificate with a rating for airplane single-engine land. The pilot owned a Cessna 150, and although he also owned an experimental amateur-built Bensen B-8M gyrocopter, and the Helicycle, he did not possess a rotorcraft gyroplane rating or rotorcraft helicopter rating. His most recent FAA third-class medical certificate was issued on August 19, 2014. He reported on that date that he had accrued about 1,200 total flight hours.

Review of the pilot's logbook indicated that he had received 21.3 total hours of dual instruction in a Robinson R22 helicopter. The last entry in the logbook was dated August 14, 2014, and showed 1.0 hours in the dual instruction column and 0.5 hours in the pilot-in-command column. The entry also showed 1.5 hours in the columns for day flight and total duration of flight, and it appeared that the number "5" in these two entries had been written over. The word "solo" had been written in the remarks column to the left of the instructor's entry for the flight, and the handwriting of the word appeared to be different than the handwriting of the instructor's entry.

Review of endorsements in the pilot's logbook showed that the handwriting in the pilot's "Initial Solo Endorsement" for the R22 was different from the handwriting in the pilot's 49 CFR 1552.3 (h) and Special Federal Aviation Regulation (SFAR) 73 Awareness endorsements. The date of his initial solo endorsement in the R22 was August 4, 2014, but there was no flight time entry for that date.

Flight Training

According to the flight instructor who provided helicopter flight instruction to the pilot in the Robinson R22, they flew a total of about 21 hours together between March 31, 2014, and August 15, 2014.

All flights were conducted in an R22 helicopter. The instructor stated that he never endorsed the pilot's logbook to authorize solo flight in a helicopter. The flight instructor added that he had no contact with the pilot after their last flight together on August 15, 2014. He was unaware of any past or planned flight attempts in the Helicycle, although he knew the pilot had purchased it.

During the flight lessons, the flight instructor observed what he considered to be the pilot's "bad habits" on several maneuvers, which he believed originated from the pilot's gyrocopter and airplane experience. The pilot would also occasionally lose control of the helicopter while hovering and during maneuvers.

After each instructional flight, the flight instructor reviewed the flight lesson with the pilot and discussed with him his negative habits and instances of loss of control as they worked to improve his helicopter piloting skills. In their discussions, the flight instructor told the pilot that his skills were not yet sufficient for solo flight, including flight in his Helicycle.

AIRCRAFT INFORMATION

The Helicycle was a single-seat, experimental amateur-built helicopter. It was equipped with a two-blade, semi-rigid main rotor and was powered by a Solar T62-32, 150 shaft horsepower, turboshaft engine.

The main rotor was fully harmonized, and the flight control system included a modulated collective pitch system. The helicopter was also equipped with elastomeric thrust bearings, control friction devices, and an electronic throttle control.

According to FAA records, the helicopter was issued a special airworthiness certificate on October 6, 2008, after it had been assembled from a kit. It was purchased by the pilot on March 10, 2014.

According to maintenance records, the helicopter's most recent condition inspection was completed on May 5, 2011. At the time of accident, the helicopter had accrued about 51 total hours of operation.

METEOROLOGICAL INFORMATION

At 1553, the reported weather at Nashville International Airport (BNA), Nashville Tennessee, located 21 nautical miles southwest of the accident site included: calm winds, 10 miles visibility, scattered clouds at 4,200 ft, broken clouds at 6,000 ft, temperature 26° C, dew point 16° C, and an altimeter setting of 30.08 inches of mercury.

FLIGHT RECORDERS

The helicopter was not equipped with a cockpit voice recorder or flight data recorder, nor was it required to be by federal regulations. However, a camcorder that was being operated by the pilot's friend whose property the accident occurred on captured most of the liftoff and accident flight.

Five files from the camcorder were provided to the NTSB. Each file contained video and audio of the helicopter on the day of the accident; however, only two of the five files were used by investigators. (The remaining three files did not have sufficient content for analysis.) The audio was extracted from each file at its native sample rate of 48,000 kHz and converted to a mono wave file for sound spectrum analysis.

The first video, which was 26 seconds long, captured the pilot seated inside the helicopter with the engine powered on at the start of the video with the observer directly facing the helicopter. The helicopter began a hover from standstill at 8 seconds and then started moving forward 4 seconds later. The helicopter flew past the observer at 21 seconds and continued off into the distance. Only the last 12 seconds of this file were used for sound spectrum analysis.

The second video, which was 11 seconds long, captured the helicopter coming towards the observer from a distance. The helicopter was heard passing by the camera when the camera panned out at 6 seconds. An unidentified sound was heard, and the camera panned back to the helicopter at 8 seconds and showed the helicopter descending in an inverted attitude until impact.

A spectrogram was generated for the extracted audio track of each file. The frequencies associated with the turbine and main rotor rpm were identified from the first file and used as a baseline of analysis for second file. Doppler effect was present in the first file and was used to calculate airspeed during forward flight.

Evaluation of Takeoff

The main rotor frequency was determined to be 20.3 Hz, which resulted in a main rotor rpm of about 615 rpm. This value remained constant before and after passing the observer. The speed of the helicopter as it passed the observer was estimated to be 33 knots. The frequencies identified were consistent with a normal takeoff under takeoff power.

Evaluation of Event

In the second video, the airspeed was determined to be about 83 knots. The orientation between the observer and the helicopter could not be established; therefore, the actual airspeed may have been higher than calculated.

The main rotor frequency was determined to be between 20.3 Hz and 23.3 Hz, which resulted in a main rotor rpm of about 699 rpm at its peak. The ratio of the calculated rpm to the nominal main rotor rpm (from the first video) was 113%.

WRECKAGE AND IMPACT INFORMATION

Examination of the accident site and wreckage revealed that, during the impact sequence, the helicopter first made ground contact with the forward portion of the cockpit. It then tumbled along the ground on a magnetic heading of about 030° for about 90 ft before coming to rest on its left side.

Examination of the engine revealed no evidence of any preimpact failure or malfunction that would have precluded normal operation of the engine. Examination of the helicopter's structure and flight control system did not reveal evidence of any preimpact failures or malfunctions which would have precluded normal operation of the flight control system.

A piece of angle iron was discovered in the debris field along with numerous broken cable ties. Review of the helicopter manufacturer's published information did not indicate that it was part of either the helicopter's structure or drive train. According to the pilot's friend, he observed that the piece of angle iron was attached to the helicopter when the pilot landed and took off from his property. He said that the pilot had attached it to the helicopter's tail boom for weight and balance purposes.

MEDICAL AND PATHOLOGICAL INFORMATION

According to the FAA medical certification file, at the time of the pilot's most recent FAA medical certification examination on August 19, 2014, he reported high blood pressure treated with benazepril, a prescription high blood pressure medication that is marketed as Lotensin. He reported no other chronic medical conditions or medications to the aviation medical examiner (AME).

The AME noted no side effects or complications from the high blood pressure, identified no abnormal physical findings on examination, and issued a third class medical certificate with the following limitation: must have available glasses for near vision.

About 1 month before the accident, the AME forwarded a letter written by the pilot's primary care provider to the FAA Medical Certification Division as part of the medical certification package. In this letter, which was dated 2 days after the medical certificate was issued, the pilot's primary care provider noted his elevated blood pressure and recommended lifestyle modifications and continued use of benazepril with hydrochlorothiazide. Benazepril with hydrochlorothiazide is a combination prescription medication used to treat high blood pressure that is marketed as Lotensin HCT. Additionally, the letter noted that the pilot appeared disheveled, was agitated and fidgety, and his mood was described as very anxious and irritable. The primary care provider had diagnosed longstanding anxiety/depression and prescribed vilazodone, a medication used to treat major depression that is marketed as Viibryd. Vilazodone carries a warning regarding increased risk of suicide in adolescents and young adults.

Depression is a disqualifying condition for pilot medical certification, and, according to the Guide for Aviation Medical Examiners, an aviation medical examiner should not issue a medical certificate to a depressed pilot. The FAA will consider a special issuance of a medical certificate for depression after 6 months of treatment if the applicant is clinically stable on one of four approved medications; vilazodone is not one of these medications.

Autopsy

According to the Nashville Tennessee Office of the Medical Examiner autopsy report, the cause of death was multiple blunt force injuries. No significant natural disease was identified.

Toxicology

Toxicological testing on specimens from the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The specimens were negative for carbon monoxide, cyanide, ethanol, and basic, acidic, and neutral drugs, with the exception of diphenhydramine and sertraline, which were detected in liver and blood. Diphenhydramine was detected in cavity blood (2.171 ug/ml) and liver. Additionally, sertraline was detected in cavity blood (0.101 ug/ml) and liver, and its metabolite desmethylsertraline was also detected in blood and liver. According to an email to the NTSB medical officer dated May 23, 2016, the FAA's laboratory testing would not identify vilazodone. Aegis Crimes Laboratory toxicology testing performed as part of the medical examiner's death investigation identified 0.828 ug/ml of diphenhydramine in cavity blood.

Diphenhydramine is a sedating antihistamine used to treat allergy symptoms and as a sleep aid. It is available over the counter under the trade names Benadryl and Unisom. Diphenhydramine's accepted therapeutic range is from 0.0250 to 0.1120 ug/ml, and it carries the following FDA warning: may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery). Compared to other antihistamines, diphenhydramine causes marked sedation; it is also classed as a central nervous system depressant, and this is the rationale for its use as a sleep aid. Altered mood and impaired cognitive and psychomotor performance may also be observed. In a driving simulator study, a single dose of diphenhydramine impaired driving ability more than a blood alcohol concentration of 0.100 percent.

Sertraline is a prescription medication used to treat several conditions including depression, obsessive-compulsive disorder, panic disorder, and social anxiety disorder; it is marketed as Zoloft. Sertraline carries a warning regarding increased risk of suicide in adolescents and young adults. The accepted therapeutic range is from 0.0100 to 0.2000 ug/ml.

ADDITIONAL INFORMATION

Pilot's Rotorcraft Forum Posts

The pilot was a member of an internet rotorcraft forum and posted regularly. On September 19, 2014, he posted that he had flown the Helicycle about 3 hours that day but still needed the factory check pilot "to come and help me work out little kinks here and there, but overall the flight was great."

During the flight, he noticed that there was "a little stick shake" and "had a problem with belt slippage" that he attributed to oil leaking from the transmission filter housing onto the belts.

He stated that the factory check pilot was going to come out to install new elastomeric bearings on the rotor hub, and he was sure that "we will balance and tweak everything."

Elastomeric Bearings

According to the kit manufacturer, the elastomeric bearings were excluded from the purchase price of a Helicycle kit. The elastomeric bearings, which were part of the Helicycle rotor hub and necessary to operate the helicopter, would be withheld from the kit until the kit was assembled and ready for the customer's factory checkout. The installation of the elastomeric bearings would be performed by an authorized factory test pilot during the factory checkout, and the kit manufacturer reserved the right to withhold the elastomeric bearings until the customer had sufficiently prepared for the factory checkout.

In the case of the accident helicopter, the Helicycle had been purchased from a previous owner so it already had the elastomeric bearings installed when the pilot purchased it. On September 27, 2014, the elastomeric bearings were replaced to track and balance the main rotor during the pilot's factory checkout.

Kit Manufacturer's Requirements for Flight

According to the kit manufacturer, their policy was that customers would agree to have a factory checkout performed on their Helicycle before flight. The factory checkout consisted of a multi-day process during which the Helicycle was "checked out" and then test flown by a factory check pilot.

During the checkout, the customer also will fly the Helicycle for the first time. The factory checkout would only be scheduled following the receipt of the following items by the kit manufacturer:

- Proof of aircraft registration.

- Airworthiness certificate.

- A completed factory checkout checklist.

- Proof of solo flight in

NTSB Probable Cause

The pilot's decision to fly the improperly balanced helicopter at high speed and low altitude, which resulted in a loss of control and collision with terrain. Contributing to the accident were the pilot's depression and resulting degradation of executive function and the pilot's use of a sedating antihistamine, which resulted in impaired mental and motor skills.