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On July 10, 1999, approximately 1520 Pacific daylight time, an Alexander Van's model RV-8 homebuilt aircraft, N41VA, constructed by/registered to and being flown by a private pilot, was destroyed when it collided with terrain during an uncontrolled descent preceded by an in-flight fire during descent one nautical mile north of Lafayette, Oregon. The pilot was fatally injured. Visual meteorological conditions existed and no flight plan had been activated. The flight, which was personal, was to have been operated under 14CFR91, and originated from Arlington, Washington, earlier on the date of the accident. A fuel stop had been made at Scappoose, Oregon, between 1345-1445 hours.
An eyewitness located within about one-half mile of the crash site reported that he "heard the airplane revving its engine full force..." and "looked up to see the airplane flying level from west to east...." He further reported that the "airplane then started to nose down until it was going nearly strate [sic] down..." and that "the engine was revving full force untill [sic] it crashed and exploded..." (refer to attached witness statement). The witness, who was south of the aircraft's flight path and crash site, estimated the altitude of the aircraft as about 200 feet.
An ear witness located within one mile of the crash site reported hearing "a single engine plane engine go to a wide open throttle position for appox [sic] 2 or 4 sec[onds] and then nothing." He did not see the aircraft until after it impacted the terrain (refer to attached witness statement).
A third witness, who did not provide a written statement, was interviewed by both the investigator-in-charge and local law enforcement authorities. The interview with the Yamhill County Sheriff's Deputy (case number 99-002440) provided the following information: The witness "advised that he was in the field swathing when he saw and [sic] plane coming over the hill to the east very low and that it appeared to be on fire as there was lots of smoke coming from it. He said that it passed over the far end of the field and was about 200-300 feet high when he saw a person jump from the plane landing in the field where he had been cutting gras [sic] for seed. He said that the person striking the ground appeared to bounce about 3-4 feet into the air, the plane then went into a slight turn, banked sharply nosing over striking the ground in the uncut grass bursting into flame." The interview with the investigator-in-charge provided the following additional information: The witness reported hearing the aircraft's engine and described it as "smooth but high power" and that the aircraft was flying from west to east. He also reported that the interval between the time the pilot left the aircraft and impacted the ground was about three seconds and that the aircraft impacted the ground immediately after the pilot. He described the smoke as "black" and estimated the aircraft's altitude as 200 to 400 feet above ground.
A pilot logbook was acquired containing the pilot's name. The logbook was opened on July 29, 1977, and the final entry was observed to be dated March 22, 1999. Three flights in the RV-8 aircraft, all in N41VA, were observed entered in the logbook. These three flights (the last three entries in the log) were dated March 7th, 8th and 22nd consecutively, and totaled 6.0 hours. A tally of flight time within the log indicated that the pilot had logged 633 hours of total flight time of which 596 hours were pilot-in-command. The logbook also showed that the pilot had logged 82 flight hours in the RV-4 aircraft between March 30, 1997, and July 10, 1998, at which time the log indicated the RV-4 was sold.
The pilot's last medical examination, conducted February 25, 1999, was for a third class medical certificate and contained a special restriction and waiver. According to records maintained by the Federal Aviation Administration (FAA) the restriction stipulated that the pilot "must use hearing amplification."
A License Agreement between the pilot/builder and Van's Aircraft, Inc., found with the aircraft records, indicated that the RV-8 kit was first purchased on November 20, 1997, and issued serial number 80544 by the kit producer.
The airframe logbook showed a date of manufacture of February 1, 1999, and the first entry in the logbook was dated February 14, 1999, with a total time in service of 0.4 hours. A conditional inspection signoff followed on March 5, 1999. The following (last) logbook entry was dated May 10, 1999, and showed a total time in service of 25.0 hours.
The engine logbook and documentation showed that the original engine, a Textron Lycoming O-360-A1A, had been overhauled on October 1, 1998. The logbook also showed that the engine was installed on N41VA with 0.0 hours service on January 10, 1999, and was "inspected [and] deemed airworthy" on March 5, 1999. The last logbook entry, dated May 27, 1999, showed a total of 25.6 engine hours.
The overhaul facility, Aero Sport Power, a division of Pro Aero Engines, Inc., of Kamloops, British Columbia, issued serial number 0172 for the engine (refer to ATTACHMENT ASP-I). The engine was purchased, according to an invoice, on October 5, 1998 (refer to ATTACHMENT BOS-I). A parts list associated with the overhaul showed that four new pistons, part number LW15357 as well as four new "Aero Sport" cylinders, part number S441SP, were installed (refer to ATTACHMENT OL-I). In an email dated October 13, 1998, the overhaul facility advised the owner that "high compression pistons are not mentioned separately on the parts list as they are included in the cylinder kits" (refer to ATTACHMENT EM-I).
According to a representative of Textron Lycoming, the standard piston associated with the O-360-A1A engine is part number LW75089. This piston is defined as having a compression ratio of 8.5 to 1 resulting in a horsepower of 180 for this engine. The piston, part number LW15357, which was installed in the RV-8's engine, was associated with a later version of the O-360 engine and has a compression ratio of 9.0 to 1.
An Internet website (address: http://www.matronics.com/cgi-bin/searching/ws_script.cgi) was reviewed and a search of all emails related to the pilot's name and/or aircraft registration number was made with 288 hits received. The first hit was dated September 1998 and the last hit (the last email issued by the pilot prior to the accident) was dated July 8, 1999, and referenced 35 hours of RV-8 time. There was no evidence in any of these emails that the pilot had attempted any major engine disassembly or removed any of the engine's cylinders. Additionally, a fellow RV-8 builder at the Independence airport, who was in close contact with the pilot during the construction of N41VA, reported that he saw no evidence of the pilot's attempting any major engine disassembly or removal of any of the engine's cylinders.
A representative from TransWestern Aviation, Inc., the fixed base operator and fuel supplier at the Scappoose airport, Scappoose, Oregon, confirmed that N41VA was fueled on the afternoon of July 10, 1999. According to a fueling slip, the aircraft was topped off with 25.4 gallons of 100 aviation octane low lead fuel approximately 1345.
The aviation surface weather observation taken at 1553 at McMinnville, Oregon, four nautical miles south of the accident site, reported clear sky conditions, a temperature of 90 degrees Fahrenheit, and winds from 330 degrees magnetic at 7 knots.
WRECKAGE AND IMPACT INFORMATION
The aircraft crashed in an agricultural field on gently rolling terrain approximately one nautical mile north of Lafayette, Oregon. The accident site coordinates were determined using a hand-held GPS unit and were found to be 45 degrees 15.65 minutes north latitude and 123 degrees 6.48 minutes west longitude. The elevation of the accident site was estimated to be approximately 500 feet above mean sea level (MSL) (refer to CHART I). The accident site was also noted to be nearly midway between Scappoose and Independence, Oregon, and about three nautical miles west of a straight line between these two towns (refer to CHART II).
The pilot was found at a location bearing approximately 360 degrees magnetic and 600 feet from where the aircraft impacted the ground (refer to photograph 1 and DIAGRAM I). The location of the pilot was noted to be 46 feet beyond (on a bearing of approximately 084 degrees magnetic) a semi-circular impression in the field. A piece of the pilot's belt was found at this semi-circular ground impact site.
No aircraft parts were located outside of the immediate area of the ground impact site and a post-crash fire had destroyed much of the aircraft (refer to photographs 2 through 5). The aircraft displayed extensive compressive "telescoping" deformation and the approximate longitudinal axis was observed to be oriented along a 074 degree magnetic bearing line (tail east). All major components from the aircraft were found at the ground impact site.
The left wing displayed leading edge compressive deformation (refer to photograph 6) and small fragments of red glass were observed mixed in the soil at a point bearing 166 degrees magnetic and approximately one-half wingspan distance from the engine. Likewise, the right wing displayed leading edge compressive deformation and small fragments of green glass were observed mixed in the soil at a point bearing 023 degrees magnetic and approximately one-half wingspan distance from the engine (refer to photograph 7).
The horizontal and vertical stabilizers and their respective control surfaces remained attached at the empennage (refer to photograph 8). However, the left stabilizer and its associated elevator were heavily fire damaged and melted. The right horizontal stabilizer leading edge displayed an aftward compressive indentation just inboard of the stabilizer outboard tip which could not be associated with impacting some other part of the aircraft or ground (refer to photograph 9).
The engine sustained extensive fire damage. The propeller remained attached to the crankshaft and one blade displayed aftward bending deformation which was more pronounced toward the tip, while the opposing blade displayed similar aftward bending but with slight "S" bending towards the tip (refer to photograph 10).
Both flaps were observed to have remained attached to their respective wings. Control continuity was established from all three sets of control surfaces to the cockpit area. The fuel selector valve was examined and found to be in the "right tank selected" position. The electric fuel boost pump and switch was destroyed by fire. The engine driven fuel pump housing at the rear of the engine had sustained fire damage and was partially melted.
A distribution of aircraft parts including large pieces of deformed clear Plexiglas, sections of canopy skirt, wing skin, main wheels and wheel-pants, both separated ailerons, and engine cowling was observed progressing from the ground impact site generally towards the west. Many of these components were found in the grass at the edge of or outside of the post crash fire area (refer to photographs 11 and 12).
MEDICAL AND PATHOLOGICAL INFORMATION
Post-mortem examination of the pilot was conducted by Larry V. Lewman, M.D., at the facilities of the Oregon State Medical Examiner's offices, 301 NE Knott, Portland, Oregon, on June 13, 1999.
At the request of the investigator-in-charge, the following information was provided:
1. There was no evidence of burn or heat damage to the pilot's shirt. 2. There was no evidence of burn damage to the pilot's trousers. 3. There was no evidence of burn damage to the pilot's shoes. 4. There was broadbased blunt force impact mainly involving the right side of the face/head, right anterior shoulder and right thigh. 5. Both eyebrows and the hair at the anterior hairline were singed as confirmed by magnification. 6. There was significant singeing and burning of the hair over the right temporal-frontal scalp. 7. There was no evidence of inhaled smoke within the lungs. 8. There was no evidence of soot deposition within the nasal or mouth passages.
Toxicological evaluation of samples from the pilot was conducted by the FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma. The following findings were reported (refer to attached TOX report):
>>29 (mg/dL, mg/hg) ethanol detected in Kidney Fluid >> 3 (mg/dL, mg/hg) acetaldehyde detected in Kidney Fluid >>13 (mg/dL, mg/hg) ethanol detected in Muscle Fluid
No ethanol was reported from evaluated blood samples.
Portions of the aircraft were reconstructed at a salvage facility at the Independence airport, Independence, Oregon. Photograph 13 is a pre-accident image of N41VA. Significant points of reference in this photograph are the location of the left side NACA air intake vent, the seam line at the edge of the aft engine cowling along the edge of the firewall, the paint scheme on the aircraft, the left wheel-pant location, the canopy and the canopy skirt (left side).
A section of engine cowling from the lower left side of the engine was recovered outside of the post-crash fire area (refer to photograph 14). The white paint on the aft portion of the exterior of the fiberglass panel was observed to be moderately blistered. The trailing edge of the panel, which is normally located along the left edge engine firewall, displayed sooting and several semi-circular burn holes were observed along the aft edge. A small section of torn aluminum fuselage skin with a thin red and blue racing stripe and a portion of the NACA air intake was also recovered outside of the post-crash fire area and displayed sooting on its exterior surface. This same section of engine cowling from the lower left side of the engine was turned over and examined. Its interior honeycomb surface exhibited extensive sooting and the interior glass fabric face sheet affixed to the inside of the honeycomb was absent (refer to photograph 15).
A number of pieces of three-dimensionally cambered Plexiglas from the aircraft's canopy/windscreen were examined. Several pieces were observed to be rolled into near tube-like shapes inconsistent with the curvature of the canopy. A major section of Plexiglas was observed folded over on itself and exhibited virtually no three-dimensional curvature (refer to photograph 16). The Plexiglas was found to be hard and inflexible during its examination and displayed deformation characteristic of Plexiglas subjected to heating conditions resulting in softening prior to impact.
The left and right halves of the canopy skirt were examined. The forward portion of each skirt was reinforced with metal tubing affixed to the interior sides of the skirt. The left skirt was blistered on its exterior surface towards the forward end. When the skirt was turned over, a substantial amount of sooting was observed increasing in severity towards the forward end. A shadow pattern was evident behind a number of the reinforcing tubes and along the aft edges of the tubes (refer to photograph 17). The right skirt displayed less blistering on its exterior surface. When the skirt was turned over, a lesser amount of sooting was observed, again increasing in severity towards the forward end. Lighter shadow patterns were evident behind a number of the reinforcing tubes where they had been located prior to impact (refer to photograph 18).
The gascolator, as shown in a pre-completion photograph, had been mounted on the lower left side of the firewall (refer to photograph 19), and just inboard of the trailing edge of the engine cowling from the lower left side of the engine (refer to photographs 14/15). It was observed still partially attached to the firewall and removed for further examination. The bowl and retaining clip were noted but the top of the gascolator was melted and had been destroyed by fire (refer to photograph 20). The quick-drain shaft and spring had melted free from the low point drain-sleeve but were found nearby (refer to photograph 21).
The canopy rail lock pin, which prevents the canopy from sliding to the fully aft position (providing access to both forward and rear seats) was found installed within the track. The location of the pin would have prevented the canopy from travelling far enough aft in flight to provide access to the rear seat.
Following the partial airframe reconstruction at the salvage facility, the engine was examined. Holes in the upper engine case halves in the vicinity of cylinders one and two (both forward cylinders) were noted (refer to photograph 22). When these two cylinders were removed, the number one piston was observed to be absent and its associated connecting rod had been deformed laterally (along the engine's longitudinal axis). The piston wrist pin was still captured within the connecting rod outboard end but was displaced to one end of the pin (refer to photograph 22). The number two cylinder connecting rod was observed to have separated from the engine's crankshaft through the two arms on the crankshaft end of the rod (refer to photograph 23). Numerous fragments of metal were found within the engine's oil sump pan and inside the oil filter. The number two connecting rod cap end, both associated rod cap bolts and nuts and the two remaining sections from the rod were not found. The numbers three and four cylinders were removed, revealing each piston still connected to its respective connecting rod and thus to the crankshaft.
Although the pilot had acquired and utilized a parachute during the first approximately 25 hours of aircraft operation, he was not utilizing the parachute at the time of the accident.
The aircraft's canopy is airfoil shaped and during flight conditions would tend to create an aerodynamic low pressure condition near the top of the canopy (just aft of the seam between the windscreen and canopy).
TESTS AND RESEARCH
A substantial portion of the engine, including number's one and two cylinders, the crankshaft and associated bearings, the camshaft, all four connecting rods, and oil screen, sump and filter fragments, were shipped to the Safety Board's Office of Research and Engineering, Materials Laboratory, for further examination (refer to attached Report No. 99-225).
The examination revealed that all engine components were soot-covered and the crankshaft, which remained intact, displayed axiall compression between crankcheeks one and two. Examination of the six main (crankshaft) bearing halves showed that all bearings contained minimal wear and no evidence of localized heating (consistent with sufficient lubrication).
Examination of the number one cylinder and components confirmed the previously described connecting rod deformation and wrist pin location. Additionally, examination of the interior of the cylinder showed that the crown area contained severe peening damage.
Examination of the number two cylinder and components revealed that the number two connecting rod had separated through the two arms on the crankshaft end of the rod. After ultrasonic cleaning of the fracture surfaces a bench binocular microscope examination revealed crack arrest positions consistent with fatigue cracking that emanated from the exterior surface of the arms, and fatigue propagation was through most of the fracture surfaces.
According to the "Airframe and Powerplant Mechanics Powerplant Handbook," Advisory Circular 65-12A, published by the FAA, "A crankshaft is dynamically balanced when all the forces created by crankshaft rotation and power impulses are balanced within themselves so that little or no vibration is produced when the engine is operating." Thus, the release of the number two connecting rod and disintegration of the number one piston in the aircraft's engine could have induced significant vibrations within the engine and aircraft airframe.
On-site examination of the wreckage was conducted on July 11, 1999, after which the wreckage was verbally released to a representative of Gale's Towing & Recovery, Inc. for the purpose of removal from the site and transport to a suitable storage area. The wreckage was subsequently stored at the facilities of HLM Air Services, Inc., Independence, Oregon. Written wreckage release, exclusive of the engine and aircraft documentation/records, was accomplished on September 27, 1999, and is documented on NTSB form 6120.15 (enclosed). Written release of the engine and aircraft documentation/records was executed on January 7, 2000, and is documented on NTSB form 6120.15 (enclosed).