Aviation Accident Summaries

Aviation Accident Summary SEA00LA104

HAMMETT, ID, USA

Aircraft #1

N322KE

LUNN (Vans) RV-6A

Analysis

The owner/pilot and pilot rated passenger departed to the west from a personal airstrip in the RV-6A homebuilt aircraft. The characteristic departure, according to local residents, was for the pilot to execute 180 degree turn, and return back over the departing airstrip before proceeding on course. The aircraft impacted the ground heading north slightly northwest of the airstrip. The crush angle on the aircraft's wings was noted to be about 20 degrees nose down and relatively wings level. No pre-impact engine or control malfunction was evident, nor was there any evidence of any pilot pre-impact impairment. The aircraft's airspeed indicator read 40-50 mph at the crash site. The stall speed for the 180 horsepower RV-6A, according to the manufacturer's specifications, was 50 mph.

Factual Information

HISTORY OF FLIGHT On June 14, 2000, approximately 0900 mountain daylight time, an experimentally certificated homebuilt Lunn (Van's) RV-6A, N322KE, registered to and being flown by a private pilot, was destroyed when the aircraft collided with terrain following a loss of control during the initial climb near Hammett, Idaho. The pilot and his son, also a private pilot, were fatally injured, and a post-crash fire destroyed the cockpit/cabin area of the aircraft. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight, which was personal and local, was operated under 14CFR91, and departed the pilot's personal airstrip at his residence several minutes before the accident. Two witnesses observed the aircraft. One witness reported that the aircraft had just departed his runway and "...was doing a U-turn..." but did not observe the aircraft's ground impact. This witness heard the impact and saw the explosion. A second witness did not see the aircraft until its impact (refer to ATTACHMENTS S-I, II, and III). Residents in the area reported that historically the aircraft would customarily depart to the west, execute a 180-degree turn, and return back over the departing airstrip before proceeding on course. PERSONNEL INFORMATION According to the remains of a burned pilot logbook found at the accident site, the owner/pilot was issued a private pilot certificate on June 28, 1990. Although the dates of the entries on the log pages recovered were burned away, a total time of approximately 423 hours was noted. The owner/pilot reported a total of 350 hours flight time at his most recent third class medical examination, conducted February 28, 2000, and a restriction that he must wear corrective lenses was in effect. It was not known whether he was in compliance with this restriction at the time of the crash. The owner/pilot was reportedly the only operator of N322KE and he had been issued an FAA Repairman Experimental Aircraft Builder certificate on March 13, 2000. According to records maintained by the Federal Aviation Administration (FAA), the pilot rated passenger was issued a private pilot certificate on August 5, 1993. He reported a total of 150 hours flight time at his most recent third class medical examination, conducted July 13, 1999, and a restriction that he must wear corrective lenses for distant vision and possess glasses for near vision was in effect. It was not known whether he was in compliance with this restriction at the time of the crash. AIRCRAFT INFORMATION N322KE was a Van's model RV-6A homebuilt aircraft manufactured by the owner/pilot. According to FAA aircraft records, and the remains of a burned aircraft logbook found at the accident site, the aircraft was issued a special airworthiness certificate and experimental certification on July 8, 1999. The last readable entry in the log showed an aircraft total time of 97.9 hours and the date of this entry was unreadable. The aircraft was equipped with two seats located side-by-side, each with a set of flight controls. A 180 horsepower Textron-Lycoming O-360-A1A engine had been installed along with a controllable pitch Hartzell propeller. The amount of fuel on board the aircraft at the time of the accident was not known. According to information published by the kit manufacturer, Van's Aircraft, Inc., the stall speed for the Model RV-6A with a 180 horsepower was 55 mph (refer to ATTACHMENT VAN'S-I). METEOROLOGICAL INFORMATION The aviation surface weather observation taken at Mountain Home Air Force base 14 nautical miles west of the accident for 0855 hours on the morning of the accident reported the following conditions: Sky condition 22,000 foot scattered, visibility 30 statue miles, temperature 70 degrees Fahrenheit, dew point 41 degrees Fahrenheit, winds from 280 degrees magnetic at 9 knots, altimeter setting 30.26 inches of mercury. WRECKAGE AND IMPACT INFORMATION The aircraft crashed in an Alfalfa field into soft soil slightly south of the Snake River (refer to CHART I) and five nautical miles west-southwest of Hammett, Idaho. The latitude and longitude of the accident site was reported as 42 degrees 56 minutes north latitude and 115 degrees 35 minutes west longitude. The aircraft was observed at the initial ground impact site with its longitudinal axis oriented roughly north/south (nose north) and no evidence of any ground slide. An area measuring approximately 42 feet (north-south) and 20 feet (east-west) of singed alfalfa was observed slightly north of the ground impact site (refer to photograph 1). All major components of the aircraft were located at the ground impact site with the exception of the canopy located in the previously described singed alfalfa. The engine was observed embedded in the soil in an approximate 20-degree down pitch attitude. One propeller blade was observed protruding out of the ground (refer to photograph 2). When the propeller was extracted, the propeller hub assembly was observed to be separated at the engine crankshaft flange. The separation surfaces were characterized by 45-degree fractures (refer to photograph 3). The propeller displayed aft bending at one tip and noticeable twisting deformation on the opposing blade (refer to photograph 4). The FAA inspector reported that the blade also displayed leading edge abrasions. Both wings remained attached at the fuselage and there was substantial fire damage to the cockpit area and wing leading edges increasing in severity from the left wingtip to the right wingtip. The left wingtip remained partially attached to its wing and the leading edge of the wing displayed an upward deformation consistent with the 20-degree nose down pitch of the engine described earlier (refer to photograph 5). The right wingtip also remained partially attached to its wing and the leading edge of this wing displayed similar upwards deformation but a greater degree of aftward compressive deformation (refer to photographs 6 and 7). The aircraft's fuel tanks were located forward of the wing spar in the wing leading edge area inboard. The empennage and vertical/horizontal stabilizer and control surfaces including the left elevator trim tab remained attached with the airframe and displayed minimal fire damage. The airspeed indicator was observed to read between 40 and 50 mph and the manifold pressure indicated approximately 30 inches. MEDICAL AND PATHOLOGICAL INFORMATION Post-mortem examination of both occupants was conducted by Glen R. Groben, M.D., at St. Alphonsus Hospital, Boise, Idaho, on June 15, 2000, (case numbers OC-002 & OC-003). The Owyhee County Coroner identified the occupants at the accident site and the owner/pilot of the aircraft was recovered from the left seat while the pilot rated passenger was recovered from the right seat. Both occupants displayed fractures of both femurs. The left occupant displayed a fracture of both the right ulna and radius whereas the right seat occupant displayed no arm or hand fractures. The FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma conducted toxicological evaluation of samples from both occupants. The findings for both occupants were negative, with the exception of a finding of 1.181 ug/ml of acetaminophen (aspirin) detected in blood for the left seat occupant (refer to attached Toxicology reports). TESTS AND RESEARCH Post-crash re-examination of the aircraft revealed no evidence of discontinuity for any of the three control systems (rudder, elevators and ailerons). The electrically driven elevator trim was observed in the neutral position. The flaps were observed in the retracted position. Crankshaft and camshaft rotation and continuity was verified as well as compression on all four cylinders. Post-crash re-examination of the aircraft's engine revealed no evidence of pre-impact mechanical malfunction. ADDITIONAL INFORMATION On-site examination of the wreckage was conducted by an FAA inspector from the Boise Flight Standards District Office on June 14, 2000, after which the wreckage conditionally released for transport to Mountain Home airport pending additional examination. A post-crash re-examination of the aircraft was conducted on June 20th, and the aircraft was subsequently released to the insurance representative as documented on NTSB form 6120.15 (enclosed).

Probable Cause and Findings

The pilot's entering an inadvertent stall condition, and the lack of adequate altitude in which to successfully recover before ground impact.

 

Source: NTSB Aviation Accident Database

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