PIERCE, ID, USA
N9186F
Hughes 369HS
During an aerial survey flight, the aircraft was maneuvering to position for another run along a contour line in mountainous terrain. The flight elevation along the contour was reported about 150 feet above the ground level. The terrain was covered with deciduous and coniferous trees varying in height to about 50 feet. The surviving passenger reported that the helicopter was making a descending right turn when he suddenly felt a jolt. The passenger, seated directly behind the pilot on the left side, saw the pilots head jerk up, as the helicopter pitched straight up, then fall backwards and collided with the terrain in an inverted and nose low attitude at the base of a dead tree located on an outcropping along a ridge. This tree was taller than any of the surrounding trees and the top was broken off. This snag was also dark in coloration and void of branches. Plexiglas fragments and two rivets were found embedded in the section that broke off. Structural impact signatures noted that the helicopter came in contact with the tree on the right side lower fuselage section with rearward crushing damage through the anti-torque pedals and traveling aft to the cyclic control stick socket. Wood particles were embedded within the deformed fuselage structure and also to the forward section of the landing skids. The passenger reported that he did not detect any mechanical anomalies prior to the jolt, nor did the pilot indicate any problems over the headset prior to the collision. Post-crash inspection of the wreckage did not reveal evidence of a mechanical failure or malfunction.
HISTORY OF FLIGHT On December 28, 2000, about 1505 Pacific standard time, a Hughes 369HS, N9186F, registered to Panhandle Helicopters, and contracted by Idaho Fish and Game as a 14 CFR Part 91 three day aerial wildlife survey, collided with a tree and subsequently the ground while maneuvering in mountainous terrain about 20 miles east of Pierce, Idaho. Visual meteorological conditions were reported at the time by the passenger and a company visual flight rules flight plan was in effect. The helicopter was substantially damaged and the commercial pilot and one passenger were fatally injured. The second passenger was seriously injured. The flight had been operating in the area since about 1000 that day. The passenger reported that this was the second day of a three day aerial wildlife survey. The survey was to estimate the population density of mountain lions in the area by sighting tracks in the snow. On the day of the accident, flying activities began about 1000. At about 1445, the helicopter landed for fuel. After the fueling was complete, the helicopter took off to continue the survey. The passenger stated that the survey area was divided into 63 random sites. During each run, a contour line elevation was selected at the established coordinates. The pilot would position the helicopter about 100 to 150 feet above the contour line elevation (above ground level) and fly for approximately 12-minutes per run along the contour. The flight had just completed one 12-minute run and was positioning for a second. The passenger, who was seated in the left rear seat behind the pilot, stated that the helicopter was maneuvering around a ridge in a slow (estimated 30 to 35 mph along the contours, slower during the maneuver) descending right turn when he felt a "jolt." The passenger stated that he could see the pilots head move up very quickly, and he (the pilot) reacted very fast. The passenger reported that the helicopter then pitched straight up and paused before falling backwards, colliding with the ground in an inverted and nose low attitude at the base of a dead tree located on an outcropping along the ridge. The tree measured in height to about 100 to 120 feet. The passenger stated that he remained conscious the whole time and reported that after the crash sequence, he noted that his seat belt was broken as he did not have to release the buckle. As he was exiting the helicopter via the left side door, he grabbed a bag containing survival gear and moved away from the helicopter. Within the survival bag, the passenger found a hand held emergency locator transmitter (ELT). The passenger activated this ELT which emitted the signal that search and rescue personnel used to locate the accident site. The helicopter's ELT, installed on the cockpit center pedestal, lower right side, was damaged during the accident sequence and did not emit a signal. The passenger stated that just prior to feeling the jolt, he heard the front seat passenger say to the pilot that he believed that "this is the place where we are starting." The helicopter was turning to get into position for the run when the "jolt happened." The passenger also stated that all operations and engine noises up to that point were normal and did not change until after the jolt. All occupants were wearing helmets and able to communication with one another. The passenger reported that at the time of the accident the visibility was good and that there was no fog or clouds covering the mountains. The ground crew fueler from Panhandle Helicopters reported that he had been fueling the helicopter for the flights that lasted about two to two-and-a half hours in duration. The last fueling for the day was at about 1500. The end of the flight was planned for about 1600. The fueler stated that he put in 40 gallons of jet A fuel, which filled the tank to just below the filler spout. No other services were needed. The fueler observed the pilot complete the normal walk-around visual checks prior to takeoff. The pilot did not indicate to the fueler that there were any operational or mechanical problems with the helicopter at that time. The fueler stated that the weather had cleared and the sun was out and the sky was blue. Search and rescue personnel were notified about 1600, on December 28, 2000, when the pilot did not check-in by 1530. The wreckage was located by search and rescue personnel on December 29, 2000, about 1005. PERSONNEL INFORMATION At the time of the accident, the pilot held a commercial certificate and was rated in rotorcraft. The pilot's flight logbook number 3, dated September 1998, to present was provided for review. The logbook indicated that approximately 3,050 hours had been accumulated in all aircraft/rotorcraft, with approximately 1,925 hours as pilot-in-command. The first flight logged in the accident helicopter was dated February 25, 1999. All flights after this date to the accident date were in helicopters (Hughes 369D, and 369HS) operated by Panhandle Helicopters. The last entry logged in the logbook was dated December 27, 2000, for a total flight time of 5.1 hours, and indicated that the purpose was for cougar tracking. On the day of the accident, the aircraft flight log indicated that the aircraft hobbs at the beginning of the day was 9035.2. The hobbs at the accident site was recorded as 9039.6, for a total flight time on the day of the accident of 4.4 hours. The pilot held a class II medical certificate dated April 5, 2000, with no waivers or limitations noted. The pilot's last airmen competency/proficiency check was satisfactorily accomplished on May 30, 2000, in the Hughes 369D. WRECKAGE AND IMPACT INFORMATION The wreckage was located at N 46 degrees 21.473, W 115 degrees 18.746, in an area of mountainous terrain. The main wreckage and associated wreckage debris was positioned on a fairly level outcropping along a ridge line at an elevation of approximately 3,350 feet. The terrain to the northeast rose to about 6,000 feet, while the terrain to the southwest descended to the valley at about 2,500 feet mean sea level. The terrain was covered with deciduous and coniferous trees varying in height to about 50 feet. The ground was covered with three to four feet of snow. The helicopter was positioned inverted and nose low in the snow at the base of a lone dead tree "snag." This snag was about 80 to 100 feet in height. During the aerial viewing of the site, the top section of the snag displayed evidence of a fresh break. Scratch marks to the exterior trunk near the top were also visible. The trunk was mainly void of branches and dark in coloration. The helicopter was positioned with the nose pointing to 220 degrees. The tail boom separated as a unit from the fuselage and was located within 10 feet of the main wreckage. The tail rotor blades and tail rotor gearbox remained attached. One tail rotor blade displayed evidence of a two inch in length leading edge indentation about 12 to 14 inches inboard from the tip, while the other blade was not damaged. The horizontal stabilizer, upper vertical stabilizer, stabilizer strut and lower vertical stabilizer remained attached and undamaged. The main rotor blades and rotor mast sustained heavy impact damage. One blade was visible and severely deformed, while the remaining three blades were buried in the snow or not located at that time. The landing skids remained in place, however, impact damage was noted to the left skid gear tube which fractured just aft of the forward strut. The right skid gear tube fractured just forward of the forward strut. Wood particles were noted embedded around several of the mounting bolts on both skids. The front cockpit area and lower fuselage section was severely compromised. The fuselage forward section and the Plexiglas were broken. About 100 feet south and downhill from the main wreckage, an approximate 12-foot section of tree trunk was located. Fresh breaks were noted at both ends of the section. Along the outer surface of the trunk, pieces of broken Plexiglas were found embedded in the wood. Also embedded in the wood were two rivets with dark blue and black paint on the heads. Red and blue paint transfer was also noted on the wood surface. The wreckage was recovered from the accident site after January 1, 2001, and transported to Discount Salvage, Deer Park, Washington. Further examination of the wreckage was conducted on January 11, 2001, at Discount Salvage. The wreckage was positioned right-side up and setting on the landing skids. The cyclic control stick was not installed on the right side (passenger side). Rearward crushing impact damage to the lower fuselage section traveling forward to aft was noted on the right side and continued aft to the cyclic control stick socket. The right side anti-torque pedals were fractured at the torque tube. Evidence of wood particles were noted throughout this area in the pedals and to the lower fuselage structure. The left side (pilots side) cyclic control stick and collective control remained in place, however, the collective grip was fractured. Continuity was established from the cyclic and collective up to the main rotor mixer control rod and tail rotor control rod where the tail boom had separated. Evidence of at least one main rotor strike to the tail boom was evident. The tail boom separated about 66 inches forward of the tail boom cone. Several sections of the main rotor blades were recovered and examined. Each blade was identified and matched to the main rotor hub via the color coded red, blue, yellow and white markings. The red blade was in three sections, the blue blade in two sections and the yellow blade in one section with an additional section remaining attached to the main rotor hub. The white blade was not recovered at the time and is believed to be still at the accident site. Each blade section examined was severely deformed. The MD Helicopters participant documented the main rotor and tail rotor flight controls and reported that other than the impact damage, they were in working order. The same was reported for the engine controls. The N1 and N2 controls were intact and had full motion and movement. The participant also reported that documentation of damage to the rotor systems and drive train indicated evidence of power during the blade strike, followed then by sudden stoppage. See attached MD Helicopter statement. During the engine examination, no external damage was noted. The engine remained encased in the cowling and the surrounding structure and engine mounts were intact. No evidence of a mechanical failure or malfunction was noted. See attached Rolls-Royce Engine Investigation Report. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed at the Pathologist's Regional Laboratory, Lewiston, Idaho, on both the pilot and the front seat occupant. The Pathologist reported that the cause of death to both individuals was due to blunt trauma to the head and chest. Toxicological samples were sent to the Federal Aviation Administration Civil Aero medical Institute, Oklahoma City, Oklahoma, for analysis. The analysis was negative. ADDITIONAL INFORMATION The wreckage was released to the president of Panhandle Helicopters on February 2, 2001. The wreckage was stored at Discount Aircraft Salvage, Deer Park, Washington.
While maneuvering, clearance from an object was not maintained. A tree was a factor.
Source: NTSB Aviation Accident Database
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