N61735Hughes 369D

On July 22, 2009, about 1125 eastern daylight time, a Hughes 369D, N61735, was substantially damaged during a forced landing in an open field in Forbes State Forest, near Franklin, Pennsylvania, while enroute to a temporary landing location. The certificated commercial pilot was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was conducted under Title 14 Code of Federal Regulations Part 133.

The helicopter arrived in Pennsylvania from California on July 4, 2009, and was being contracted to gather 200 to 250 pound bags of seismic monitoring equipment from remote locations in the heavily wooded area and reposition them to the temporary landing site or another location. Since the helicopter had arrived, it had recorded approximately 72.9 hours of flight time, moving the seismic monitoring equipment within a 20-square mile area.

On the morning of the flight, the accident pilot attended a safety briefing conducted by the contracting company at 0600 along with the operator for the contract. About 0730 the pilot and operator departed the safety briefing for that day's operation. According to the operator and the company's daily time sheet, the pilot performed a pre-flight inspection of the accident helicopter, as was his custom, started the helicopter's engine about 0934, and departed at 0939. The flight returned to the temporary landing area about 1010 to re-fuel for the next flight. The accident flight departed about 1030 and flew to pre-determined locations in order to retrieve a total of 4 bags carrying seismic monitoring equipment. During the return to the landing zone, numerous personnel, including the operator, heard the pilot talking over their communication frequency. Most of the communications were "inaudible," but some heard the pilot say that he was "going into the tree[s]."

The helicopter was discovered in a clearing, approximately 250 feet from a paved highway, by a passer-by, who reported to the Safety Board investigator on-scene that there was no noise associated with the helicopter. She had heard the helicopter several times over the weeks preceding the accident; however, on the morning of the accident she did not hear it.

The pilot, age 33, held a commercial pilot certificate, with a rating for rotorcraft-helicopter. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on March 24, 2009. At that time, the pilot reported a total flight time of 2,600 hours. The pilot had completed a biennial flight review on October 27, 2007 in a Robinson R-44 helicopter. On February 27, 2009, the pilot completed a check ride with his current employer in the accident helicopter make and model. According to company records and the pilot's job application, he had 2,844 total hours of flight experience, 1,876 total hours of flight experience in Turbine-Powered Rotorcraft as Pilot in Command, and 1,252 total hours of flight experience in the accident helicopter make and model. The pilot was hired as a contract pilot on February 25, 2009 and had flown approximately 161 hours with this company since his date of hire, all of which were in the accident helicopter make and model.

The helicopter was issued an FAA airworthiness certificate on March 10, 1993 and was registered to the owner on January 4, 2002. It was equipped with an Allison 250-C20R2 engine. The 100, 200, 300-hour yearly inspection was completed on the airframe and the engine on June 29, 2009. At the time of the inspection, the Hobbs meter indicated 1,658.3 total hours, the airframe had 11,621.5 total hours, and the engine had 1,237.2 total hours and 852 cycles.

The 1130 recorded weather observation at Garrett County Airport (2G4), Oakland, Maryland, located approximately 22 nautical miles southeast of the accident location, included winds from 140 degrees at 7 knots; visibility 10 miles, scattered clouds at 2,100 feet above ground level, temperature 22 degrees C, dew point 15 degrees C; altimeter 30.19 inches of mercury.

An on-scene investigation by the Safety Board revealed that the helicopter impacted the ground in an open field 104 feet away from a wooded area which consisted of trees approximately 60 feet in height. The helicopter came to rest upright leaning slightly to the left on a heading of 170 degrees. The five main and two tail rotor blades exhibited little damage to the leading edges. Two of the main rotor blades exhibited slight coning in the positive direction and one of the main rotor blades was bent in the negative direction. The aft left part of the attached tail boom exhibited deformation, orange paint transfer, and contact marks consistent with main rotor blade strikes to the tail boom. The anti-torque control linkage was continuous from the cockpit pedals back to the tail rotor blades. There was continuity of drive from the main transmission to the main rotor and back to the tail rotor. The main rotor blade droop stop rollers exhibited no damage.

The tail rotor gearbox was able to rotate freely and oil was present in the sight glass. The under seat collective control rod was fractured and continuity was confirmed from the fracture point up to the upper flight controls at the main rotor hub. Movement of the controls was prevented due to the damage to the underside of the fuselage.

The right side of the horizontal stabilizer was bent downward beginning approximately 10 inches from the vertical fin. The right landing skid was separated from the fuselage and was lying about 2 feet from the helicopter. The left skid was separated and was lying next to the fuselage. The left side and belly of the fuselage exhibited extensive crush damage, consistent with a high vertical descent rate. The helicopter's left pilot seat box was crushed, consistent with a high vertical descent rate, and all the other seats had been previously removed to allow for a greater useful payload capability.

The aircraft fuel system comprised of a main fuel tank and an auxiliary fuel tank. The main fuel tank bladder was breeched during the accident sequence; however, no residual fuel was detected in either fuel bladder, auxiliary fuel tank, or on the ground in the vicinity of the aircraft. The auxiliary fuel tank shut-off valve handle located on the left side of the pilot's seat was found extended or in the "CLOSED" position. The main fuel shut-off valve located on the left side of the instrument panel was found in the "OPEN" position.

The fuel lines were inspected and approximately three drops of fuel was discovered in the line to the fuel nozzle from the check valve. The fuel lines from the fuel control to the check valve and from the aircraft fuel tank to the filter were void of fuel. Aircraft battery power was applied and the "low fuel" indicator light illuminated on the instrument caution and warning panel. A functional test of the fuel sending unit could not be accomplished due to impact damage.

The engine was examined on scene and had remained attached to the main wreckage. The gas producer throttle lever indicator pointed to 90 degrees on the quadrant; however, due to impact damage, rigging continuity could not be verified. The power turbine governor throttle lever indicated a maximum fuel flow condition. Due to damage to the fuselage, collective rigging to the power governor could not be verified. The 5th stage compressor bleed valve was found in the "OPEN" position.

Oil was present and clean; the magnetic plugs were clean of foreign matter.

The gear box vent line was separated at the attachment point on the engine. The N1 rotated and was continuous to the starter generator and the first stage turbine wheel and was verified utilizing a borescope. The N2 was unable to be rotated. The engine auto-relight system was in the auto position.

The external load and the line that attached it to the helicopter were located in the wooded area 281 feet in the direction of 076 degrees from the helicopter. The external load total weight was estimated at 1150 pounds. The external load, which consisted of three orange bags and one yellow bag, each consisted of seismic recording equipment, with each weighing approximately 250 pounds. The line, which was a thick braided nylon rope and an electrical cord, was approximately 200 feet in length. A four hook metal assembly was attached to the helicopter's external cargo hook via a metal clevis. The assembly allowed for delivery of loads to multiple locations and weighed approximately 150 pounds.

An autopsy was performed on the pilot on July 23, 2009, by Cyril H. Wecht and Pathology Associates, Inc., Pittsburgh, Pennsylvania. According to the forensic pathologist report, the pilot sustained multiple blunt force traumas.

The FAA's Civil Aerospace Medical Institute performed forensic toxicology on specimens from the pilot and no drugs of abuse were detected.

Global Position System (GPS)

The GPS unit was sent to the NTSB's Recorders Laboratory and downloaded. Data from the unit was extracted and revealed that the helicopter departed at 0936:36, and returned to the landing site at 1032:57. The helicopter then departed at 1039:42 and the recording ended at 1129:19 at a GPS location in the vicinity of the accident location.

Fuel Control Unit and Power Turbine Governor testing

On August 13, 2009, with oversight provided by the FAA, the fuel control unit (FCU) and the Power Turbine Governor (PTG) were tested at the Honeywell South Bend, Indiana Facility. The FCU throttle shaft and drive shaft moved freely. The FCU was mounted on the test bench and was tested as received; all test points were within limits and no abnormalities were noted during the test. The PTG was examined and the throttle shaft and drive shaft moved freely. The PTG was mounted on the test bench and was tested as received; all test points were within limits and no abnormalities were noted during the test. The testing revealed that both units were functioning normally at the time of the accident and demonstrated no condition which would have contributed to the accident.

Engine Investigation

On September 29, 2009, the engine was examined and disassembled at a local facility with oversight provided by the NTSB investigator. The N1 system was continuous and rotated from the compressor to the starter generator; however, the N2 was not able to rotate. Further examination revealed that the exhaust collector tunnel was deformed near the top support section and precluded the No. 5 bearing from rotating. The No. 5 bearing was removed and rotated with little resistance. The compressor was intact with no external damage noted and no debris was discovered within the compressor. Blade tip rub and witness marks were noted on the 4th stage compressor wheel and blade track. The damage was consistent with forces applied to the vertical axis of the helicopter during compressor rotation. A longitudinal fracture was noted in the outer shroud of the 3rd stage turbine wheel. The 3rd stage turbine wheel and associated bearings were forwarded to the National Transportation Safety Board's Materials Laboratory for further examination. The bleed valve and fuel nozzle were removed and tested with no contributory issues discovered.

3rd Stage Turbine Wheel

The 3rd stage turbine wheel and associated bearings were sent to the NTSB's Materials Laboratory for testing. The longitudinal fracture through the outer shroud was opened for examination and the fracture traces and arrest lines within this region were consistent with fatigue progression. No mechanical damage or metallurgical abnormalities were noted at the fatigue origin or crack locations. The associated bearings were examined and rotated smoothly and exhibited no apparent damage.

Operator Interview

In a telephone interview, operator/ground personnel reported to the Safety Board investigator that he required the pilots to land with at least 70 pounds of fuel on board. He further reported that he "wanted to see some space between the empty mark and the needle." The operator/ground personnel stated that after one particular flight, there was "one time it was very low and there was no space between the mark and the needle" and the minimum requirement was reiterated to the accident pilot. The operator also informed the Safety Board that the helicopter would usually be loaded with 150 pounds of fuel and that a flight was normally 30 to 40 minutes in duration. The fuel was provided from a tank located on the operator's truck which was refilled at a local airport. He reported that the external load consisted of bags that carried seismic activity monitoring equipment which weighed 200 pounds each, and that they "did not calculate a load sheet" for each flight.

Seismic Monitoring Company

Employees of the seismic monitoring company reported to the Safety Board investigator that the bags weighed between 200 and 250 pounds but most were probably about 250 pounds. They also reported that each bag was to be attached to the external line manually and that the individual that attached the last bags on the accident flight did not report any problems with, or changes in the sound of the helicopter.

Helicopter's owner GPS report logs

A GPS report log, which recorded the position approximately every 5 minutes, was supplied to the Safety Board from the owner of the helicopter. On the morning of the accident, the helicopter was started at 0934:34 and indicated a GPS altitude of 2,630 feet. The first recorded change in speed was at 0941:49 and indicated an altitude of 2,727 feet. The log revealed that the helicopter flew at altitudes ranging from 2,354 feet to 2,761 feet and returned to the departure point at 1034:05. The accident flight departed at 1044:25 and the altitude recorded ranged from 2,091 feet to 2,768 feet. The days prior to the accident, 10 flights were conducted and the flight times ranged from approximately 18 minutes to 59 minutes in duration.

Rolls-Royce 250-C20R Series Operation and Maintenance Manual

According to Rolls-Royce data, Section 72-00-00, Table 2, "Performance Ratings for Normal Operation," the cruise performance and fuel burn could vary depending on the power setting. The variation was from 211.1 up to 239.8 pounds per hour fuel consumption. Specific fuel consumption at these ratings did not include the takeoff power fuel burn, which would have been a maximum of 23 pounds of fuel consumed during a 5-minute takeoff power setting.