Tulalip, WA, USA
N7190K
Robinson R22 Beta
The pilot landed his helicopter on a bluff adjacent to a hexagonal wood frame structure, which he had been constructing. Although he had landed at the site on previous occasions, this was the first time he had done so with the structure in place. He subsequently walked down and visited a relative and then walked back to the helicopter after advising the relative he would return later. Shortly thereafter the relative heard a "boom" and then noted a fire on the bluff. There were no eyewitnesses to the accident and it could not be determined whether the accident occurred prior to departure, during departure or during a return to the landing site after departure. A post crash fire destroyed most of the helicopter and the wood frame structure. No ground impact marks were noted and there was no evidence that any part of the helicopter struck any of the several trees/dead snags at the perimeter of the bluff. The pilot had an estimated 5,192 hours of total flight experience of which 772 were in rotorcraft and 374 hours were in the accident helicopter. Winds were light and variable and visual meteorological conditions existed at the time. Post crash examination of the non fire-consumed remains of the flight controls and the helicopter's O-360-J2A engine revealed no evidence of pre-impact mechanical malfunction. All major components with the exception of the anti-torque pedals and instrument console were identified/located at the accident site. One main rotor blade was released when the blade retention bolt separated at both ends in shear overload, and the blade displayed minimal leading edge damage. The opposing blade's outboard 4 foot section separated from the inboard section and the inboard section remained attached to the rotor mast. The inboard blade section displayed upward bending and the separation point displayed abrupt downward bending. Three feet of the outboard 4 foot section was destroyed by fire but the leading edge strip was found. The outboard one foot tip was not recovered. There was a light impact impression at the top of the main rotor shaft (outside diameter) indicating mast bumping and the elastomeric teeter stop was absent. The opposing stop was crushed. An indeterminate quantity of Quinine was detected in the pilot's blood and liver during toxicological evaluation.
HISTORY OF FLIGHT On July 22, 2003, approximately 1115 Pacific daylight time, a Robinson R22 Beta helicopter, N7190K, registered to and being flown by a private pilot, was destroyed during a loss of control and in-flight collision with terrain near Tulalip, Washington. The pilot was fatally injured and a post-crash fire destroyed the helicopter and an adjacent wood frame building. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was personal, was operated under 14 CFR 91. A close acquaintance of the pilot reported that the helicopter was kept at the pilot's father's business (refer to CHART I) and would have originated from this location on the date of the accident. She further reported that the pilot's intention for the flight on the morning of the accident was to visit friends and that he had landed at the accident site on several previous occasions. She also remarked that the previous landings had taken place prior to the wood frame structure having been built. The tower manager at Paine Field (Snohomish County airport, Everett, Washington) reported that the only known radio contact with N7190K occurred at 1038:50. She reported that the pilot radioed that he was "...off of Tulalip heading for Hat Island and then we'll be inbound to Paine Field..." (refer to CHART I). At 1122 Snohomish County Emergency Dispatch received a notification of a fire and dispatched fire crews to the accident site. There were a number of witnesses who saw the helicopter prior to the accident or heard the helicopter operating in the vicinity of the accident site. There were no eyewitnesses who actually witnessed the accident scenario. An individual who was related to the pilot reported that approximately 1030 on the morning of the accident, the pilot visited her. She indicated that he had landed the helicopter at the site of his recreational building on the bluff above, and had walked down to her residence on Arcadia Road. After a brief stay the pilot indicated he would return later and walked back up the hill. Shortly thereafter she heard a "boom" and then noted a fire up on the bluff (Snohomish County Incident Report number SO03-16387). A witness reported seeing the helicopter takeoff and fly toward Camano Head and then turn around and return. The witness subsequently heard a "boom" and observed black smoke. Another witness saw the helicopter flying in from the southwest and indicated that he had seen this helicopter before. He stated that about ten minutes later he saw smoke. Another witness observed the helicopter fly overhead and then head toward the bluff after which he heard a loud "thud" (Snohomish County Incident Report number SO03-16387). None of the witnesses reported seeing any evidence of unusual flight behavior. PERSONNEL INFORMATION The pilot's father provided an estimated breakdown of the pilot's total flight time. He reported a total of 4,420 hours of single and multi-engine fixed wing time and a total of 5,192 hours of combined helicopter and fixed wing time with the helicopter time broken down as follows (refer to Attachment FS-I): 374 hrs Hughes 500D 2 hrs Robinson R44 396 hrs Robinson R22 According to records maintained by Robinson Helicopter, the pilot attended a flight training program for his newly acquired R22 helicopter consisting of two days of ground school (6-7 September 2000) and one day (8 September 2000) of flight training/checkout which included 2 hours of R44 time. The pilot reported to Robinson that upon his arrival for training in September 2000, he already had logged 33 hours of R22 time and 2 hours of R44 time. The total 396 hours of R22 time minus the 33 hours prior to his acquisition of N7190K (363 hours) was estimated to be the maximum amount of pilot in command time the pilot logged in the R22 as well as the approximate total helicopter time for N7190K. * According to the pilot's third class medical issued 23 October 2001, the pilot was assessed with a restriction that he "must wear corrective lenses." It was not known whether the pilot was in compliance with this requirement at the time of the accident. AIRCRAFT INFORMATION Copies of airframe and powerplant logs from N7190K were provided showing the helicopter's last annual/100 hour inspection being conducted on 26 February 2003, at a total airframe/engine time of 308.8 hours. A review of the copies showed no individual or repetitive maintenance problems. The total time on both the engine and airframe were estimated to be approximately equal to the pilot's R22 pilot in command time (363 hours). * METEOROLOGICAL INFORMATION Aviation surface weather observations recorded at Snohomish County airport (Paine Field [PAE]) indicated a consistent visibility of 10 miles all morning and afternoon of the accident and a consistent altimeter setting (atmospheric pressure) of 30.11 inches of Mercury all morning. The 1053 surface weather observation reported winds variable at four knots with a temperature of 19 degrees Celsius. Paine Field bears 10 nautical miles south of the accident site and is 606 feet above mean sea level (MSL). WRECKAGE AND IMPACT INFORMATION The helicopter crashed on a bluff (plateau) slightly less than one mile northwest of Tulalip, Washington. The accident site coordinates were determined using a hand held GPS unit and were found to be 48 degrees 04.457 minutes north latitude and 122 degrees 18.112 minutes west longitude. The elevation of the accident site was approximately 260 feet MSL. Refer to CHARTS I and II. The plateau on which the crash site was located was approximately 150-200 feet in diameter and nearly level with an approximate -4 degree down slope toward the southwest. The southern edge of the plateau sloped abruptly down to sea level. Situated in the approximate center of the cleared plateau was a hexagonal wood frame structure, which was reported by acquaintances of the pilot to be a recreational facility/house he had been constructing at the site. Two dead snags (tree trunks) were noted south-southwest of the main wreckage at the edge of the plateau and a moderately tall conifer tree was noted at the western boundary of the plateau. No impact marks were observed on any of these three trees and there were no discernible ground scars that could be associated with the accident. The majority of wreckage was distributed in the northern half of the plateau between the structure and the plateau's northern boundary (refer to DIAGRAM I and digital image 1). A post-crash fire consumed much of the helicopter and destroyed the wood frame structure; and precluded any specific determination of pre-impact contact between the helicopter and the structure. The largest piece of wreckage consisting of the engine/firewall, transmission, pylon and the inboard two-thirds of one rotor blade was observed lying on the ground with the helicopter's vertical axis parallel to the surface of the ground (90 degrees nose down). The entire forward cabin area (forward of the firewall) was absent (refer to digital image 2). The next largest pieces of wreckage were observed distributed from this main piece in an arc from the north to the west and included the tailboom with its vertical and horizontal stabilizers and the tail rotor assembly (refer to digital image 3), one long section of skid, and both the main and auxiliary fuel tanks. The pilot was observed clear of the main wreckage and alongside the wood frame structure approximately 22 feet southwest of the engine. Both the 19.2 gallon (usable) main fuel tank and the 10.5 gallon (usable) auxiliary fuel tank were observed lying on the ground and displayed fire damage. A general burn pattern in the grass surrounding each tank was noted. A large number of fragments of broken Plexiglas, cockpit flight controls and associated linkages, and cockpit structure were observed distributed in an arc from the northeast to the east of the main wreckage. The entire opposing rotor blade was observed lying in short grass approximately 75 feet east-northeast of the engine (refer to digital image 4). The remaining one-third (outboard three foot portion) of the rotor blade retained at the pylon was destroyed by fire, and the outboard one foot blade tip section was not located. The leading edge cap from this three foot section of blade (exclusive of the missing tip) was found within a burned woodpile approximately 10-15 feet west of the engine (refer to digital image 2). Additionally, a section of skid toe was located 125 feet south-southwest of the engine near the base of two dead snags at the edge of the plateau. The rudder pedals and instrument panel/console were not located. Inspection of the main rotor blades revealed that the intact blade along with its spindle had separated from the main rotor hub at the junction point of the top and bottom mating surfaces between the rotor fork and the spindle. The attach bolt was separated with the center section of the bolt shaft remaining within the spindle and the two end bolt sections were observed lying on the ground not far from the main wreckage. All four bolt fracture surfaces displayed horizontal shear signatures (refer to digital images 5, 6, 7 and 8). The entire leading edge of the blade displayed virtually no impact marks with the exception of 1) a small area midspan showing abrasion marks at the leading edge and progressing across the surface of the blade and 2) the last (outboard) one foot section where noticeable scratch marks nearly perpendicular to the blade's chordline and originating at the leading edge were noted. The midspan abrasions were gray in color and closely matched the color of a fragmented concrete birdbath lying in close proximity to the blade. The opposing blade's inboard two-thirds section remained attached at the hub with the attach bolt retaining the spindle to the hub. The pitch link was disconnected and the blade had rotated approximately 180 degrees out of its normal position. This section of blade displayed a noticeable upward (concave from the upper side of the blade) permanent deformation except at the outboard separation point where a distinct downward bending was observed (refer to digital image 9). The outboard three foot section displayed upward bending most noticeably at the outboard end (adjoining the missing one foot tip section). The inboard separation matched the outboard surface of the inner blade section and also displayed an abrupt downward bend at the separation area (refer to graphic image 10). The main rotor hub was examined and the elastomeric teeter stop associated with the retained blade displayed lateral compressive crushing damage (refer to digital image 11). The opposing elastomeric teeter stop (released blade) was absent and the teeter stop bracket was broken and deformed (refer to digital image 12). The upper portion of the main rotor drive shaft outside diameter abeam the spindle for the released blade displayed a horizontal dent or impression characteristic of contact with the outer-upper edge of the hub assembly (refer to digital image 13). The tailboom separated just aft of the fuselage attach point. The horizontal stabilizer displayed little damage. The lower vertical fin displayed some bending deformation and the tail stinger was bent upward. The upper vertical fin displayed light leading edge damage at the intersection of the horizontal stabilizer and was deformed aft with buckling deformation along the trailing edge adjacent to the hub attach point (refer to digital image 14). Post crash examination of the non fire-consumed remains of the flight controls and the helicopter's O-360-J2A engine revealed no evidence of pre-impact mechanical malfunction. MEDICAL AND PATHOLOGICAL INFORMATION Norman Thiersch, M.D., conducted post-mortem examination of the pilot at the facilities of the Snohomish Medical Examiner's facilities, Everett, Washington, on July 23, 2003, (case number SCME 03SN1292). The FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma conducted toxicological evaluation of samples from the pilot. All findings were negative with the exception of an indeterminate quantity of Quinine detected in both blood and liver (refer to attached TOX report). ADDITIONAL INFORMATION On-site examination of the wreckage was conducted on July 22 and 23, 2003, after which the wreckage was verbally released to a family representative. Written wreckage release was accomplished on July 29, 2003, and was documented on NTSB form 6120.15 (attached). Those items retained (two blade retention bolt ends and an approximate 3-foot section of outboard leading edge blade section) were returned to a family representative on March 16, 2004, (refer to Attachment FX-I).
A loss of control for unknown reasons.
Source: NTSB Aviation Accident Database
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