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On November 27, 2004, about 0935 Pacific standard time, a Robinson R22 Beta helicopter, N4029Q, registered to and operated by a private individual, was destroyed while maneuvering when it experienced an in flight break-up followed by impact with the terrain during an uncontrolled descent near Arlington, Washington. The flight instructor and the pilot-rated student sustained fatal injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 CFR Part 91 instructional flight. The local flight departed the Arlington Municipal Airport (AWO), Arlington, Washington, at approximately 0930.
In a statement submitted to the National Transportation Safety Board investigator-in-charge (IIC), two witnesses reported that on the morning of the accident, at approximately 0920, they observed the helicopter being started and lifting off the ground before moving to the run-up area, which is located at the southeast corner of runway 34-16. The witnesses stated that the helicopter then settled onto the ground facing north-northwest [320 degrees], and remained there for the next 2 minutes at takeoff RPM. The witnesses reported that the helicopter then lifted off the ground to about 3 to 4 feet before turning slightly to the right, then making a left turn of approximately 320 degrees before slowly accelerating and aligning itself parallel to the taxiway. The witnesses stated that the helicopter then slowly climbed to 75 to 100 feet above ground level (agl) before departing to the north, and at all times the helicopter sounded normal and was very smooth in flight.
Numerous witnesses reported seeing the helicopter flying between 300 and 500 feet agl and heading north before experiencing an in flight breakup and impacting terrain. One witness reported hearing what he thought "…was the engine making a loud noise, like a large diesel truck roaring, then there was a large, loud bang north of my barn and some pieces fell to the ground." A second witness reported hearing the helicopter "...make a loud bang, then watched it fall from the sky." A third witness reported seeing a small helicopter flying off to his left, "...and [in] a matter of seconds I saw smoke from where the helicopter was flying. I saw the aircraft crash into the field." A fourth witness reported seeing a small helicopter flying north from AWO, "...and as it disappeared into the distance I heard a large prolonged 'shuddery boom,' and then no more helicopter engine noise."
The NTSB IIC and two Federal Aviation Administration (FAA) aviation safety inspectors traveled to the accident site. The helicopter was located in an open field approximately 2 nautical miles north of AWO. There was no post crash fire. After an initial onsite examination of the aircraft and documentation of the debris field, the helicopter and all associated components were recovered and moved to a secured location at the Arlington Municipal Airport, where representatives from the NTSB and the FAA would examine the wreckage in greater detail at a later date.
The helicopter, which had been purchased by the pilot-rated student three days prior to the accident, had been rebuilt by a local certificated airframe and powerplant mechanic. The mechanic personally delivered the helicopter to the pilot-rated student at approximately 1800 on November 24th. In a telephone interview with the IIC on November 28th, the mechanic reported that on November 16th and 17th, he conducted test fights of the helicopter with the assistance of another pilot. The test pilot stated in a telephone interview with the IIC that he observed no anomalies with the aircraft during the test flight. The test pilot also revealed that on November 25th, the day after the new owner purchased the helicopter, he personally flew with him for approximately 45 minutes, letting the pilot/owner take control of the aircraft during various portions of the flight. Additionally, the mechanic had a second pilot conduct a test flight on November 24th. In a written report to the IIC, the second test pilot stated that the mechanic requested that he take the helicopter up and put it into an autorotation, checking to make sure that the main rotor blades were adjusted properly. The test pilot reported taking the helicopter up to 1,000 feet, dropping the collective, and observing the rotor RPM to be low. The pilot stated, "I landed and reported my findings to [the mechanic], [who] made some adjustments. I did another flight and found the rotor RPM was now where it should be. At the time of my flight this ship had the same doors on it that I fly with (Tech-Tool doors)." The mechanic reported that the total time for all of the test flights was 4.1 hours.
In a statement provided to the IIC dated November 29, 2004, the mechanic reported that the helicopter's annual inspection was completed and the aircraft was delivered to the pilot-rated student about 1800 on November 24th. The mechanic further reported that the Tech-Tool doors were properly installed and that the [door] pins were all in place. The mechanic stated that on November 24th, prior to delivering the helicopter to the pilot-rated student, "...I told him that he would have to reinstall the original factory doors before flying the helicopter, because I had not finished the weight and balance for the Tech-Tool doors."
Two witnesses provided the IIC with statements relative to their personal observations during the days prior to the accident. The first witness reported that after observing the helicopter being test flown on November 24th and put back in front of its hangar, he noticed that the [door] pins were not in the doors. The witness further reported that on Friday, November 26th, he again noticed that the helicopter's [door] pins were not installed. The second witness reported that about 1100 on the day before the accident, November 26th, while in the owner's hangar looking the helicopter over, "I commented to [the owner] that the cotter pins were missing or not installed to hold the doors on." The witness stated that the owner told him he was aware of this and that there were a couple of small scratches on the left door window that he would have to remove.
The flight instructor, who occupied the left pilot seat, was a full time employee for a local emergency medical air ambulance operator. The flight instructor held a rotorcraft-helicopter airline transport pilot certificate, with commercial privileges for airplane single and multiengine land, and instrument airplane. The pilot also possessed a flight instructor certificate for airplane single-engine, rotorcraft-helicopter, and instrument airplane and helicopter. The flight instructor possessed an FAA Class 1 medical certificate dated March 16, 2004, with a limitation to wear corrective lenses. The pilot reported on his most recent airman medical application a total flying time of 8,100 flight hours, with 150 hours accumulated in the previous 6 months.
The pilot-rated student, seated in the right seat, was receiving his first instructional flight in the helicopter, which he had just purchased three days prior to the accident. At the time of the accident the pilot-rated student held a private pilot certificate for single-engine land airplanes. The pilot also possessed an FAA Class I medical certificate dated March 8, 2004, with a limitation to wear lenses that correct for distant vision, and possess glasses that correct for near vision. On the application for the medical certificate, the pilot reported his total flight time was 300 hours, with 25 hours flown in the previous six months.
The two-seat Robinson R22 Beta helicopter, serial number 1529, was issued a standard airworthiness certificate on May 7, 1991. A review of the helicopter's maintenance records revealed the most recent annual inspection was completed on November 24, 2004, with a total airframe time of 2728.3 hours. The Hobbs hour meter read 4.1 hours at the last annual inspection and 4.5 hours at the accident site.
The aircraft had a Textron Lycoming O-320-B2C engine, serial number L-171189-39A. Total time on the engine at the last annual inspection was 502.1.
In a statement provided to the IIC on November 28, 2004, the certificated airframe and powerplant mechanic reported that during the rebuild of the helicopter the tail rotor gearbox was sent to Robinson Helicopter Company to be repaired; total time on the gearbox was 575 hours, with a time between overhaul (TBO) of 2,200 hours. The mechanic further reported that the overrunning clutch was also sent to Robinson Helicopter Company to be repaired; total time on the clutch was 575 hours, with a TBO of 2,200 hours. The mechanic stated that the main rotor blades were timed out, with blade life being 2,200 hours; the blades had 13 to 14 hours left on them when the helicopter was sold. The mechanic reported the tail rotor blades had accumulated 832.5 hours, and, were life limited at 5,520 hours, the main rotor transmission was new with zero time, and the actuator had a total of 218 hours, with a TBO of 2,200 hours.
In a subsequent conversation with the mechanic who rebuilt the helicopter, the mechanic stated to the IIC that the reason the helicopter was being rebuilt was that the pilot-rated student had requested that the mechanic rebuild the helicopter to his specifications. The mechanic stated that the rebuild did not commence until the pilot-rated student made the request; there was no repair work done to the helicopter prior to this time.
At 0853, the Automated Surface Observing System (ASOS) at the Snohomish County Airport/Paine Field (PAE), located 17 nautical miles south-southwest of the accident site, reported wind 300 degrees at 9 knots, visibility 10 statute miles, light rain showers, scattered clouds at 1,700 feet, broken clouds at 2,500 feet, overcast clouds at 5,000 feet, temperature 4 degrees C, dew point 2 degrees C, and an altimeter setting of 30.12 inches of Mercury. Rain began at 29 minutes after the hour.
At 0935, the AWO Automated Weather Observing System reported wind calm, visibility 10 statute miles, overcast clouds at 2,000 feet, temperature 5 degrees C, dew point missing, and an altimeter setting of 30.17 inches of Mercury.
At 0953, the PAE ASOS reported wind 320 degrees at 10 knots gusting to 18 knots, 280 degrees variable to 340 degrees, visibility 10 statue miles, scattered clouds at 2,300 feet, broken clouds at 2,700 feet, overcast clouds at 3,400 feet, temperature 5 degrees C, dew point 2 degrees C, and an altimeter setting of 30.14 inches of Mercury.
WRECKAGE AND IMPACT INFORMATION
The helicopter came to rest in open pasture tilted on its left side at an angle of about 10 degrees, on a magnetic heading of 135 degrees. A global positioning system (GPS) revealed that the accident site was at latitude 48 degrees 11.564 minutes North and longitude 122 degrees 09.017 minutes West at an elevation of 56 feet mean sea level (msl). The debris path was oriented along a magnetic heading of 315 degrees, covering a linear distance of approximately 1,325 feet, and a lateral distance of about 800 feet. The beginning of the debris path was evidenced by various pieces of small Plexiglas, followed by larger pieces of Plexiglas in a southeast to northwest orientation.
A detailed examination of the debris field revealed that the right door, which was intact and exhibited minimal damage, was located 309 feet south-southeast of the impact site. Components of the left door were found in varies locations along the debris path and prior to the main wreckage, with the left door handle located 315 feet southeast of the main wreckage. The tail rotor gearbox was located 385 feet west-southwest of the main wreckage. The gearbox assembly and the tail rotor assembly were separated from the aircraft but remained connected as one unit. The tail rotor drive shaft was separated from the tail rotor's gearbox assembly linkage and located 698 feet south-southeast of the main wreckage. Tail rotor blade #2 was found 485 feet southeast of the main wreckage, while tail rotor blade #1 was about 480 feet southeast of the main wreckage, and approximately 25 feet southwest of tail rotor blade #2. The inboard 7 inches of both tail rotor blades remained attached to their respective hub plates. The empennage assembly, comprised of the vertical and horizontal stabilizers was separated from the tail rotor gearbox assembly and located 635 feet south-southeast of the main wreckage site. Surface signatures of the component were consistent with separation in overload. The forward section of the tail cone assembly, approximately 25 inches in length, remained partially attached to the helicopter's upper frame assembly. Two additional sections of the tail cone were also found south of the main wreckage; one piece with a DANGER decal was located 715 feet southeast of the main wreckage, while a piece which displayed "29Q" was found 733 feet southeast of the main wreckage.
An examination of the helicopter's driveline revealed that the drive belts were both intact and in place. Neither belt exhibited indications of rolling or twisting. The lower actuator bearing was trapped by the crushed cooling fan and earth and could not be checked for free rotation. The belt tension actuator was fractured at the upper bearing attachment point. The upper actuator bearing was free to rotate a few degrees, but was constrained by the forward flex coupling contacting the frame. The forward flex coupling was bent, but intact. The main rotor gearbox contained blue oil and was free to rotate at least one full turn of the output shaft. The mast tube appeared to be straight, but was fractured at the top of the gearbox. The mast was bent at the top of the main rotor gearbox. The droop stops for both main rotor blades were intact and in place. Mast bumping was indicated as the result of droop stop tusks and root fitting hub contact. Mast damage was also observed under the teeter stops.
Main rotor blade SN 8772A was intact and exhibited trailing edge compression buckling. It was bent slightly downward in the inboard portion and upward near the tip. Streaks of a red substance were present near the leading edge of the blade, about 33 to 40 inches from the blade tip. There was also a streak of a red substance on the blade's upper surface approximately 80 inches from the blade's tip. Main rotor blade SN 8786A was fractured approximately 2 feet from the coning bolt. The aft portion of the blade had separated from the spar over a span of about 3 feet outboard from the spar separation. Streaks of a red substance were observed near the leading edge of the blade in an area from approximately 22 inches to approximately 32 inches from the blade tip.
The intermediate flex coupling was detached, and the flexplate arms had separated from the tail rotor driveshaft yoke. The tail rotor driveshaft was intact, but was bent about two-thirds of the way to the aft end. The tail rotor driveshaft damper bearing was free to rotate. The tail rotor driveshaft damper assembly was separated from the bearing and the tail cone mount point.
The aft flex coupling was separated; the flexplate arms had separated from the tail rotor gearbox input yoke. The flexplate arms were bent rearward.
The tail rotor gearbox was free to rotate at least one full turn. The gearbox sight glass exhibited blue oil. The tail rotor slider bearing assembly was free to rotate at least one full turn.
The tail rotor hub was intact. Both tail rotor blades were fractured at approximately 8 inches from the center of rotation. Tail rotor blade SN 5907D exhibited significant deformation and separation of the leading edge near the tip, as well as some yellow material transfer. Tail rotor blade SN 5927D exhibited chips in the paint near the leading edge.
The cockpit/cabin area was destroyed. Cockpit documentation of the aircraft's instruments was not possible on site.
The aircraft's right skid was visible lying on the right side of the aircraft imbedded in soft terrain. The left skid was not visible, having been buried into the soft, wet terrain under the left side of the helicopter.
The aircraft's engine was buried in the soft, wet terrain. Examination and documentation of the engine was not possible on site and was delayed until the aircraft was recovered to a secure location.
MEDICAL AND PATHOLOGICAL INIFORMATION
An autopsy was performed on the flight instructor at the Snohomish County Medical Examiner's Office on November 29, 2004. The cause of death was attributed to blunt force injuries.
Toxicological samples of both pilots were sent to the Federal Aviation Civil Aeromedical Institute, Oklahoma City, Oklahoma. Both pilots tested negative for carbon monoxide, cyanide, ethanol and drugs.
TESTS AND RESEARCH
On December 2, 2004, the engine was inspected by a representative of Textron Lycoming under the supervision of the NTSB IIC, and three representatives from the FAA at the Arlington Municipal Airport, Arlington, Washington. The examination revealed that the carburetor was separated from the oil sump, the venturi was separated at the throttle butterfly, and the fuel inlet screen was missing. The carburetor's metal floats were dented, the throttle linkage was broken loose, and no presence of fuel was noted. The helicopter's main fuel strainer was recovered and no contaminants were observed. The air filter was destroyed. An examination of the left magneto revealed that while it was broken loose from the engine, it was not fully separated. Although the #3 outlet of the magneto would not spark, all other outlets produced spark when rotated by hand. The right magneto was not damaged and passed a functionality test with no anomalies noted. The oil sump was partially separated from the crankcase, and no oil was observed. The oil suction screen was not recovered. Crankshaft and drive train continuity was verified through the accessory housing. Thumb compression was obtained on all cylinders. The starter ring gear support was broken radially around the crankshaft attach points. The engine's exhaust and intake systems were destroyed. The alternator sustained impact damage and was bent aft.
An examination and reconstruction of various pieces of Plexiglas, which comprised the helicopter's left windscreen, revealed a black impact strike mark that measured 24 inches in length and 5 inches in width, oriented on a diagonal plane to the windscreen's vertical axis on the left upper side of the windscreen. The black mark appears to be consistent with a main rotor blade strike. A template of the black strike mark was overlaid on an exemplar R22-Beta helicopter's left windscreen to provide relevant visualization and proper orientation of the strike mark.
Components of the helicopter's left door and tail rotor were sent to the National Transportation Safety Board Materials Laboratory, Washington, D.C., for examination and analysis. The components consisted of tail rotor blade "A", the left door handle and frame, and a portion of the door latching mechanism. The materials engineer reconstructed the components to their relative locations and reported the damage (see attached NTSB Materials Laboratory Factual Report No. 05-052). The engineer reported that two primary impact areas were visible at or near the leading edge at the tip of the blade. The more inboard area was in a black stripe region and had a rounded contour. Adjacent to the leading edge, black paint was observed. The further outboard impact area was in a white stripe region and was approximately 1 inch long with very flat features. In this area the aluminum sheet metal had cracked and folded in on itself. In both the black and white stripe impact areas yellow transferred debris was observed, with additional black streaking marks observed in the white stripe areas. The leading edge portion of the tail rotor blade, which contained the two impact areas, was cut out and examined in the scanning electron microscope (SEM). Energy dispersive x-ray spectroscopy (EDS) analysis of the impact area was performed, the results of which are contained in the above referenced NTSB Materials Lab report.
The left door frame consisted of two mating red sections, with one section containing the handle. The hinge mechanism consisted of a triangular plastic piece, two metal rods, and a fractured aluminum bracket that connects to the handle. A visual examination revealed that the entire door was painted white, with the top coat being red and translucent when viewed in cross-section at high magnifications.
Examination of the aluminum bracket revealed that the fracture had features consistent with overstress, without any impact damage observed. On the lower end of the bottom rod multiple parallel angled tears were observed. Adjacent to these areas pinkish transferred material was observed, which was also observed on a nearby metal washer. From the EDS analysis it appeared that the pink transfer on the door hinge contained compounds containing cadmium and titanium, whereas the door red paint did not contain cadmium. Also, in the impacted area of the tail rotor blade mostly elements consistent with the white or black paint were observed, though local areas containing yellow debris consistent with a lead compound were observed.
Of the hardware and components available for examination, only the door handle bracket had a flat enough area of approximate size to fit the flat impact area in the white paint region at the tip of the tail rotor blade. However, the bracket piece did not have any impact marks and no metallic transfer/scraping was visible in the impact area, which did have yellow transferred debris (also not found on the bracket). With respect to the rounded impact area in the black paint on the blade leading edge, the door hinge bottom rod could fit the radius of the impacted area. However, no sources of pink paint were present on the blade to account for the transferred material adjacent to the tears in the rubber coating on the rod. Refer to the above referenced Materials Lab report (NTSB Materials Laboratory Factual Report No. 05-052) for a detailed analysis of the EDS examination.
A subsequent examination of components was requested by the IIC to confirm paint transfers. Components submitted to the NTSB Materials Lab included a main rotor blade piece, two tail cone pieces, tail rotor #2 leading edge piece, and a rod from the door latching mechanism.
The materials engineer reported that examinations found red and white paint-like material on the leading edge of the main rotor blade, and that the larger piece of the tail boom was flattened and fractured with a large area of smeared pink material. The outer surface of the tail boom was primarily painted white but also had a red area. Examinations of cross sections of the paint found a relatively thick layer of red paint applied over a thick layer of white paint and all was covered with a clear top coat. The smeared pink material on the tail boom appeared to be a mixture of the adjacent red and white paint layers. The EDS spectra from the main rotor blade and the smear on the tail boom were consistent with mixtures of the original paint layers on the tail boom.
Additional examinations of the rod from the door latching mechanism uncovered an area of pink material transferred directly to the steel rod. A close elemental match was found when compared to that of the materials on the leading edge of the main rotor blade.
The tip of the main rotor blade was painted yellow. A yellow colored material on the damaged leading edge surfaces of the tail rotor blade from the accident helicopter was documented in NTSB Materials Laboratory Report 05-052. A comparative EDS analysis was conducted relative to the yellow colored material on both components. Refer to NTSB Materials Lab Report No. 05-123 for the findings of this examination.
On January 12, 2005, at the facilities of Tech-Tool Plastics, Incorporated, of Fort Worth, Texas, and under the supervision of an FAA aviation safety inspector from the FAA's Rotorcraft Directorate, Forth Worth, Texas, the helicopter's left door, fragmented in multiple pieces, was examined by Tech-Tool personnel. The examination revealed multiple impact fractures were present and that the weather door seal supplied by Tech-Tool was missing; there was no door weather seal or any adhesive present at all. Of the two nylon screws required to be in place to maintain proper adjustment on the door assembly in the fuselage door opening, one screw was intact; the second one [screw] was broken. It was also observed that there was no impact damage around the hinges. The top door hinge was intact and undamaged, while the bottom door hinge was bent. The examination further revealed that the inside of the door handle had been painted; Tech-Tool does not paint the inside of the door during manufacture or prior to shipment. Examination of the rubber window seal ("Z" seal) used in Tech-Tool's "quick change rubber mount window" revealed that it had been glued to the frame and window in several places. Tech-Tool representatives said that they do not install these seals with any type of adhesive.
An FAA inspector, who witnessed the examination, reported that the left door's lower hinge pin was longer than the upper hinge pin. According to the aircraft's Supplemental Type Certificate (STC) the upper hinge pin should be the longer pin. The door's manufacturer related that this installation is used to assist in installation of the door, allowing one pin to be inserted before the other. The inspector also reported observing the interior side of the door painted black; doors delivered by Tech-Tool are not painted. The inspector further reported that the weather seal was missing from the outside of the door, and that according to the manufacturer could cause the door to have more of a loose fit than normal. The inspector stated that a repair appeared to have been made to an area on the interior side of the door near the top, and that Tech-Tool personnel did not remove any paint to identify any part of the repair. The inspector also reported that during the examination the manufacturer mentioned that all doors are custom fit to each specific aircraft when installed, and that once a door has been fit to a particular aircraft it should not be installed on a different aircraft. The inspector concluded that it was not determined if the cotter pins, which secures the door to the hinge, were installed in the door prior to the accident.
An additional visual examination by the IIC of both door's door pin holes and retaining door hinge holes revealed that none of the holes exhibited any deformation or elongation signatures.
On March 8, 2005, under the supervision of the IIC, the helicopter's clutch shaft was examined at the maintenance facilities of Classic Helicopters, located at Boeing Field, Seattle, Washington. The initial observation revealed that the clutch would not function properly prior to disassembly; however, once the seal plate was loosened, the clutch would rotate. Further inspection revealed that the seal was damaged by impact, which limited the roller bearing from rotating.
TECH-TOOL DOOR REPAIR
In a report submitted to the IIC, the certificated airframe and powerplant mechanic who rebuilt the helicopter reported that he purchased both TECH-TOOL doors in August, 2002. The mechanic further reported that an initial inspection of the doors revealed that the left door had two cracks in the fiberglass frame, and that the window itself only had a few small scuffs. The mechanic stated that during the rebuilding phase of the helicopter, the pilot-rated student who was purchasing the helicopter, said that he would like to buy the TECH-TOOL doors from him, and that he and a friend of his, who worked on fiberglass for a living, would repair the left door. The mechanic further stated that a few weeks later the new owner brought the doors back to the mechanic's hangar to see how they fit the helicopter. The mechanic said he inspected the doors and that the new owner had done an exceptional job of making the doors fit. The mechanic continued by further stating that the new owner then asked him if he would paint them, which he did to the current paint scheme of the aircraft. The mechanic reported, "After I finished painting [the new owner] reinstalled the windows and installed the weather stripping around the frame." The mechanic further reported that he was not involved in the actual repair of the doors, only that he painted the doors and returned them to the new owner.
The helicopter, minus NTSB retained components was released to the owner's representative, AV-Tech Services, LLC, Kent, Washington, On September 6, 2005. All retained parts were subsequently returned to the owner's representative on February 2, 2006.