NTSB Factual Report

HISTORY OF FLIGHT

On November 2, 2008, about 1812 central standard time, a Robinson R-44 helicopter, N300FX, registered to a private individual, was substantially damaged when it impacted a river in Gallatin, Tennessee. The certificated private pilot was killed. The solo instructional flight was operated by Noble Aviation LLC., under the provisions of 14 Code of Federal Regulations Part 91, and no flight plan was filed. Night visual meteorological conditions prevailed at the time of the accident. The flight departed Lebanon Municipal Airport (M54), Lebanon, Tennessee, at 1800, enroute to Cornelia Fort Airpark (M88).

According to witnesses in the local area, about 1810, they heard the helicopter in the immediate area. They stated that they believed that it crashed in the Cumberland River just west of the State Road (SR) 109 bridge. One witness stated that he heard two distinctive "Wap Wap" sounds, then nothing. Another witness stated that she heard a "metal to metal" sound, then the impact. She believed that something had hit her metal boat dock. However, examination of the boat dock revealed no damage.

Radar data indicated that the helicopter flew to the river, then flew to mid channel, and followed the river’s path as it turned to the left. The helicopter then crossed over the SR 109 bridge and disappeared. No altitude readouts were associated with the radar data.

The pilot was located and recovered on November 11, 2008; the main wreckage was located on November 16, 2008, and recovered on November 18, 2008.

PERSONNEL INFORMATION

The pilot, age 43, held a private pilot certificate with an airplane single-engine land rating, issued on August 4, 2005. He also held an FAA third class medical certificate, issued on August 26, 2008, with no restrictions. The pilot reported on his latest medical application that he had accumulated 180 civilian flight hours in all aircraft.

According to the pilot’s flight instructor, at 1805, the pilot departed M54 for a solo night flight to fulfill the night solo flight requirements for a helicopter add-on rating. It was to be his second and final night solo flight to meet a 5-hour solo experience requirement. The pilot had flown the same route on Friday, October 31, 2008, beginning about 1800, central daylight time, and flew for a total of 2.6 hours.

AIRCRAFT INFORMATION

The four-seat, single engine helicopter was manufactured in 2001. It was powered by a Lycoming O-540-F1B5, 260-horsepower reciprocating engine. The latest annual inspection was performed on October 1, 2008. The helicopter’s total time was 685.0 hours, and the time since inspection was 27.0 hours.

METEOROLOGICAL INFORMATION

The nearest weather reporting station was at Nashville International Airport (BNA) Nashville, Tennessee, located 22.0 miles on a heading of 256 degrees. At the following: wind variable; visibility, 10 statute miles; sky clear; temperature, 14 degrees Celsius; dew point 6 degrees Celsius; altimeter setting 30.26 inches of mercury.

According to U.S. Naval Observatory information, the end of nautical twilight occurred at 1746, and the moon was in its crescent phase.

WRECKAGE INFORMATION

The helicopter, which was found submerged in about 16 feet of water, was recovered using a flat top barge and crane. The helicopter was recovered in two pieces: the cabin and main rotor system, and the tail boom and tail rotor system.

On May 12, 2009, a detailed examination was performed on the helicopter at Atlanta Air Recovery in Griffin, Georgia. The nose and chin area appeared to have sustained the most direct impact damage. The front of the cabin, from the cyclic box forward, and the floor and console were separated, but tethered by control cables and wiring. The front right seat support area was compressed upwards from the belly. The roof, windshield bow, windshields, all four doors and associated door frames were separated from the fuselage. The aft bulkhead was separated from the right side of the firewall and folded over onto the left side of the cabin.

The main fuel tank remained attached to the airframe and sustained very little damage with the exception of a puncture in the inboard skin adjacent to the airframe. The auxiliary fuel tank was separated from the airframe, dented on top of the inboard skin and had a puncture adjacent to the main rotor gearbox mount. The crossover fuel line was separated at the elbow in the auxiliary fuel tank and at the fitting in the main tank. The vent lines were clear and both finger screens were clean.

The tailcone was separated at the second bay. The top surface forward of the separation was collapsed. The edges of the skin at the separation were angular and jagged, consistent with overload. Just forward of the aft tailcone bulkhead, the skin was buckled and the aft flex coupler (tail rotor driveshaft) displayed evidence of having contacted the inside of the skin while still rotating. The empennage sustained damage that appeared to be consistent with contact with the river bottom.

The engine cowling was separated from the airframe. The right side cowling sustained more damage than the left side. The cooling fan had slight impact damage around its outer edges. The aft face of the upper drive sheave had rotational scoring marks around its circumference. The forward side of the clutch actuator had scoring marks adjacent to the upper sheave face and on its aft side adjacent to the engine cooling fan which ran in the same direction as rotation of the sheave and fan.

Main rotor flight control continuity was confirmed from the cyclic and collective to the swashplate. Both main rotor blade pitch change links were separated. The tail rotor flight controls had two disconnects. One at the forward end of the C121-9 push/pull tube and the other in the C121-17 push/pull tube in the same area as separation in the tailcone. The edges of all the separations appeared angular and jagged, consistent with overload.

The main rotor driveshaft was rotated by hand with no anomalies noted. One main rotor blade was cut near the root during recovery. It was missing approximately 3 feet of skin and honeycomb at the tip with the exception of a 10-15” section of lower skin. The spar was bent up at the tip and bent back and down in the inboard area.

The other blade was separated 2’6” outboard of the pitch change boot. The edge of the spar at the separation was angular and jagged, and folded down. The outboard section of the blade was not recovered. The coning bolt and spindle sustained some deformation and the teeter stop was crushed across its center. The tail rotor driveshaft was separated in the same area as the tailcone separation. The edges of the separation were twisted. The tail rotor gearbox was rotated by hand with no anomalies noted. The tail rotor blades were undamaged. No damage was noted to the airframe which would have prevented normal operation prior to the impact.

Examination of the engine found it attached to the engine mounts. No radial scoring was noted on the inside surfaces of the cooling fan shroud. The engine was removed from the airframe and partially disassembled to facilitate the examination.

Oil and water were found in the engine. The engine was rotated by turning the cooling fan and continuity of the crankshaft to the rear gears and to the valve train was confirmed. Thumb compression and suction were observed at all four cylinders as the engine was rotated.

The magnetos remained attached to the engine and were removed and rotated by hand. Both magnetos produced spark at all four leads. The sparkplugs exhibited worn normal appearance. The starter and alternator remained attached to the engine and no damage was noted. The engine was not equipped with a vacuum pump.

The carburetor remained attached to the engine, and the induction air box was damaged. The carburetor heat valve was about 1/3 open. The carburetor heat control in the cockpit was in a fully forward position. The mixture control at the carburetor and in the cockpit was in the full rich position. The throttle control at the carburetor was about ¼ inch from the idle position. The cockpit throttle control was damaged. Blue stains were noted in the inlet of the carburetor throttle bore. Green stains were noted at two sides of the carburetor. The carburetor was removed and partially disassembled. The fuel inlet screen was absent of debris. The bowl screw safety washers were in place and the screws were snug. A small amount of water and no fuel was found in the carburetor bowl. The white plastic floats were in place and moved freely with hand pressure. A small circular indentation was noted on the rubber surface of the needle valve consistent in location with the contact area between the needle and seat. No damage to the seat was noted.

The helicopter fuel strainer was disassembled and found to contain water. The fuel strainer screen had a small amount of debris covering about 5 percent of its surface.

Oil was observed on the dipstick when it was removed. Oil drained from the oil filter when it was removed. Water drained from the engine when the oil suction screen was removed. No metallic debris was noted on the oil suction screen or the oil filter media.

No damage was noted to the engine which would have prevented normal operation prior to the impact.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot on November 12, 2008, by the Tennessee Department of Health and Environment Office of the State Medical Examiner, Nashville, Tennessee. The autopsy finding reported the cause of death as probable drowning, with minor blunt trauma injuries.

Forensic toxicology testing was performed on specimens from the pilot at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. Results revealed the presence of ethanol, N-propanol, and N-butanol in tissue specimens. No fluids were available for testing.

NTSB Probable Cause

The pilot's inadvertent descent into water as a result of the dark night and limited outside visual references.