ANC02FA057
ANC02FA057

HISTORY OF FLIGHT

On June 21, 2002, about 2319 Alaska daylight time, a Hughes OH-6A helicopter, N345SD, was destroyed during an in-flight collision with terrain while maneuvering, about 15 miles west-southwest of Central, Alaska. The helicopter was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. The private pilot/operator sustained serious injuries, two of the three passengers aboard were seriously injured, and the third passenger was fatally injured. Instrument meteorological conditions prevailed in the area of the accident, and no flight plan was filed. The flight originated at Eagle Summit, elevation about 4,400 feet msl, and was bound for Circle Hot Springs, Alaska, about 8 miles southeast of Central.

On-site interviews were conducted by the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on June 22. Witnesses said an engaged couple was transported to Eagle Summit in the helicopter for a mountaintop wedding ceremony. Witnesses/wedding guests said when they arrived on Eagle Summit in their personal vehicles, it was windy, but visibility was good, and the clouds were high above the summit. They said they could see worsening weather approaching from the north, and shortly after the helicopter arrived, the weather closed in, and it began to snow. They said visibility was reduced to 100 to 300 feet in wet, heavy, blowing snow. The wedding ceremony was concluded quickly, and the pilot voiced concerns about having to leave the helicopter on the mountaintop over night. The pilot and his wife boarded the helicopter and occupied the front two seats, and the bride and groom occupied the two rear seats. Witnesses said the helicopter lifted off of the ground, made a right turn, and disappeared into the blowing snow en route to Circle Hot Springs. They said they had to remove an accumulation of wet, heavy snow from their cars prior to descending along the summit access road to reach the Steese Highway en route to Circle Hot Springs. About two-tenths of a mile east of the summit access road, on the Steese Highway, the wedding guests spotted the crashed helicopter. It was lying on its belly, facing the highway, in an open, down-sloped area, about 60 yards north of the highway. The tail boom, tail rotors, and main rotor system were separated from the helicopter, and the engine was still running. The occupants of the helicopter were evacuated from the helicopter by the wedding guests, and moved to the highway. Due to the remoteness of the area, the occupants were transported to the hospital by private automobile. The witnesses said the helicopter engine was still running at a high rpm when they left the area.

During an interview with the IIC on July 12, 2002, the pilot said he had flown his wife, and his brother and his brother's fiancée, from Circle Hot Springs to Eagle Summit for a summer solstice wedding ceremony. The ceremony was to be performed about midnight ( midnight in this region of Alaska, at this time of year, is still during daylight hours ). He said he had flown to the area earlier in the day to check the location. He said high ceilings and good visibility had prevailed throughout the day, but the wind was strong when he went to check the area. He said the flight from Circle Hot Springs to Eagle Summit is about 20 minutes. The pilot said when they left Circle Hot Springs for Eagle Summit en route for the wedding ceremony the visibility was greater than 10 miles, and the ceiling was about 8,000 feet msl. He said when they landed on Eagle Summit the winds had died down somewhat from his earlier trip to the summit. He said while they waited for all of the guests to arrive, a line of dark clouds descended on them from the north. He said as the guests arrived it started to snow and the ceiling and visibility decreased. He said the ceremony was concluded rather quickly because of the deteriorating weather conditions. The pilot said after the ceremony everyone was going to meet at Circle Hot Springs. He said as the helicopter lifted off for departure the ceiling was about 600 feet and the visibility was two miles. He said it had stopped snowing. The pilot recalled taking off, making a right turn, and heading downhill toward the road that would lead them back to Circle Hot Springs. He said he could not recall any of the circumstances just prior to, or related to, the accident. He said there were no mechanical problems with the helicopter.

PILOT INFORMATION

The pilot held a private pilot certificate with FAA ratings for airplane single-engine land and helicopter. The pilot did not hold an instrument airplane or instrument helicopter rating. The pilot was issued an FAA Third Class Medical Certificate on July 3, 2001. According to information received from the pilot, he had accumulated 502 total flying hours, 126 of which were in helicopters. All of the 126 helicopter hours were in the make and model of the accident helicopter. The pilot had accumulated 2.2 hours of simulated instrument flying time, and .2 hours of actual instrument flying time. The pilot did not provide information with respect to the date of his last FAA Flight Review.

HELICOPTER INFORMATION

The accident helicopter was an ex-military OH-6A, which received FAA certification on March 21, 2001. The helicopter was not equipped for instrument flight. At the time of the accident, the helicopter had accrued a total airframe time of 4,388 hours, and 89 hours since the last annual inspection. The engine had accrued a total of 2,466 hours, and 596 hours since overhaul.

METEOROLOGICAL INFORMATION

The closest official weather reporting station is at Fairbanks, Alaska, about 130 miles southwest of the accident location. At 2153 Fairbanks reported winds 300 degrees at 15 knots with gusts to 21 knots. The visibility was 10 statute miles, and the temperature and dewpoint were 51 and 32 degrees F respectively. The sky condition was reported as few clouds at 4,500 feet msl and overcast at 7,000 feet msl. The altimeter setting was 29.81. The altitude of the weather station at Fairbanks is 453 feet msl.

The Fairbanks Next Generation Weather Radar (NEXRAD) loop with a start time of 020621/23:01 and an ending time of 020622/01:02 shows a line of heavy precipitation that transits the area of the accident from west-northwest to east-southeast at the time of the accident.

Numerous wedding guests who saw the helicopter takeoff were interviewed. They all reported high winds and heavy wet blowing snow at the time of the takeoff. Visibility estimates ranged from 50 to 300 feet, with the sky obscured and no discernable cloud bases. All the witnesses said they had to remove an accumulation of heavy wet snow from their cars and proceed with caution down the summit access road to the Steese Highway because of the poor visibility.

A witness, who was not a party to the wedding, was on the summit at the time the helicopter took off. During an interview with the IIC he said that he was a pilot, and when the helicopter landed visibility and sky conditions were good, but the winds were picking up and gusting. He estimated gusts of over 20 knots. He said he watched as the wedding progressed and the weather deteriorated. He said after the wedding ceremony the wedding party got into the helicopter. He said he assumed they got in the helicopter to get out of the weather, which was strong winds, blowing snow, sky obscured, and visibility of less then 100 feet. He said he was surprised when the helicopter's engine started, but thought they were just going to turn the heater on. He said he was more surprised when the helicopter picked up into a hover. He said from inside his camper, about 50 yards from the helicopter, he could only see the red beacon light on the tail, and he could make out the faint outline of the helicopter. He said the helicopter made a hovering right turn and then started forward and disappeared northbound into the blowing snow. The witness provided the IIC with a video tape of the wedding, the deteriorating weather conditions, and the helicopter's departure. The witness said he did not know the helicopter crashed until approximately 40 minutes later. He said the weather cleared and he saw a military helicopter descend toward the highway on the north side of the summit. He said he walked to a point on the summit where he could see the Steese Highway, and the accident site.

Wedding guests said they drove their cars down the summit road northwest bound for about one-quarter mile to the Steese Highway. Once on the Steese Highway they said they drove for less than one-half mile eastbound, and spotted the helicopter on the north side of the highway, about 50 yards from the highway. They said the sky was still obscured and it was snowing.

WRECKAGE AND IMPACT INFORMATION

The terrain sloping down from Eagle Summit to the Steese Highway varies in pitch from gently sloping about 10 degrees to a moderate slope of about 30 degrees in places. The slope is covered with tundra, sparse low growing shrubs about three feet tall, and punctuated with low rock outcroppings. The view from the summit to the highway is unobstructed. The Steese Highway cuts east to west along the north side of the summit hill about 300 feet below Eagle Summit, and extends eastbound along the top of a ridge. The highway is a two lane gravel roadway with shoulders, which is about 30 feet wide. The north edge of the roadway drops off abruptly about 40 degrees for about six vertical feet, and then decreases in pitch angle to about 20 degrees, and then to about 10 degrees where the helicopter came to rest.

The wreckage of the helicopter was located on the north side of the Steese Highway about one-half mile east of the Eagle Summit rest area. The fuselage was on the downhill side of the highway, about 60 feet from the highway. The nose of the helicopter was pointed on a heading of 153 degrees magnetic, toward Eagle Summit. The transmission, rotor head, and one rotor blade lay about 12 feet directly behind the fuselage. The tail boom lay about 6 feet to the right and just behind the fuselage, with the aft end of the boom pointed toward the nose of the helicopter. The tail and tail rotor assembly lay about 6 feet directly in front of the nose. The remaining three main rotor blades were located on the left side of the helicopter, one at the nine o'clock position about 60 feet from the helicopter, one at the eight o'clock position about 30 feet from the helicopter, and one at the seven o'clock position about 60 feet from the helicopter. The tailskid and fairing were found in the brush along the north side of the roadway, about 60 feet from the nose. One-half of one tail rotor blade was found on the roadway's north side. All the major components of the helicopter were found at the accident site.

Ground scars were located on the north edge of the highway. Rocks in these ground scars had red paint transfers. One-half of one tail rotor blade was found adjacent to these scars. The tail rotor blades have red painted tips. The helicopter's tail skid and fairing were also found near these ground scars. The tail skid tube was bent rearward and broken at its attachment bracket to the tail. The skid tube fairing exhibited rearward flex folding along the leading and trailing edges, with skin distortion along its longitudinal axis. The rivet line along the top of the fairing had rearward tearing at its tail boom attachment point.

Vegetation, up to three quarters of an inch in diameter, on the sloped embankment of the north side of the roadway, had vertical chop/slash marks.

The fuselage lay on its belly with the nose facing the roadway. The main landing skids were spread apart and the heels of both skids were buried in the ground 12 to 14 inches. The upper cabin plexiglass was broken out, and the support structure flexed inward. The instrument pedestal and center console were intact. The support structures for the front two seats were collapsed and the floor pans bent downward. All the cabin doors were bent or broken open. The rear seat mounts were broken from the aft bulkhead/firewall. The transmission deck and support structure were separated from the helicopter and located at the rear of the helicopter attached to the transmission. The engine compartment's clamshell doors were open, and the engine was rotated downward about 30 degrees from its normal position in the engine compartment. There was evidence of a ground fire in the area of the engine's exhaust.

The transmission, main rotor head, and one blade were located about 12 feet to the rear of the fuselage. All four main rotor blade grips and associated hardware remained attached to the rotor head. The engine drive shaft separated at the transmission's input quill flex-pack. The tail rotor drive shaft was separated at the transmission's tail rotor output quill.

The tail boom was located aft and to the right side of the fuselage. The tail boom exhibited rotational tearing at both ends.

The tail and tail rotor gearbox were located at the front of the fuselage. The tail rotor drive shaft exhibited rotational tearing at the gearbox. Both tail rotor blade grips and one blade were still attached.

One of the main rotor blades was attached to the rotor head and transmission assembly located at the rear of the fuselage. A second blade was located about 30 feet from the fuselage at the eight o'clock position, and the two remaining blades were located about 60 feet from the fuselage at the seven and nine o'clock positions. All four blades exhibited span-wise 'S' bending and chord-wise twisting, as-well-as leading edge and tip damage.

Multiple ground scars were found about 15 feet in front of the nose of the helicopter. These ground scars were perpendicular to the longitudinal axis of the fuselage.

ADDITIONAL INFORMATION

The video tape of the helicopter's departure taken by the witness, who was not a wedding guest, is included in the public docket for this accident.


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