GRAND RIDGE, FL, USA
N220KM
REHER, KENT O. RV 6
Pilot reported to ATC that he was descending from 13,500 feet to 11,500 feet. When passing 11,500 feet the pilot reported he was descending to 9,500 feet. No further communication was made with the pilot. Radar data showed the aircraft descended normally until passing 10,000 feet. At that point the aircraft descended rapidly and was lost from radar at 5,200 feet. Eyewitnesses observed the aircraft in normal flight at about 10,000 feet. The aircraft's wing rocked back and forth and the aircraft then nosed over and descended vertically with the engine operating at high rpm until ground impact. Postcrash examination of the aircraft revealed all components necessary for flight were located on or around the main wreckage. No evidence to indicate precrash failure or malfunction of the aircraft structure, flight controls, or engine was found. No evidence of in-flight bird contact was found. The aircraft kit manufacturer reported that he has not seen any stability or control problems that would cause uncontrolled vertical descent. The pilot was reported to be in good health and good spirits before the flight.
HISTORY OF FLIGHT On August 27, 1993, about 1347 central daylight time, a Kent O. Reher RV-6, N220KM, registered to Kent O. Reher, descended into the ground at Grand Ridge, Florida, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was destroyed and the airline transport-rated pilot was fatally injured. The flight originated at Mobile, Alabama, on August 27, 1993, about 1237. Federal Aviation Administration (FAA) recorded communications indicated that after takeoff from the Mobile Regional Airport en route to Pompano Beach, Florida, the pilot contacted the FAA Mobile Departure Control for radar advisories. Radar contact with the flight was established. At 1248, the flight was transferred to the FAA Pensacola Departure Control for further radar advisories. The flight was at 7,500 feet at this time. At 1252, the pilot reported he was climbing to 9,500 feet. At 1257, the pilot reported he was climbing to 11,500 feet. At 1259, the flight was transferred to the FAA Jacksonville Air Route Traffic Control Center for further radar advisories. At 1314, the pilot reported that he was climbing to 13,500 feet. At 1320, the pilot reported level at 13,500 feet. At 1343:27, the pilot reported he was descending to 11,500 feet. At 1344:57, the pilot reported he was descending to 9,500 feet. No further communications were received from the pilot and the pilot did not respond to further communications from the FAA Jacksonville Center. (See attached FAA communication transcripts and summaries.) Recorded radar data from the FAA Jacksonville Center indicated that between 1333:19 and 1343:23, the flight maintained 13,500 feet while on an easterly heading. At 1343:23, the flight began a descent and at 1345:36, the flight descended through 10,400 feet. At 1346:00, the flight was at 9,100 feet and at 1346:24, the flight was at 8,300 feet on a heading of 092 degrees and a ground speed of 188 knots. At 1346:49, the flight was at 5,200 feet on a heading of 086 degrees and a ground speed of 162 knots. No further radar contact with the aircraft was made. The last recorded position was North latitude 30 degrees, 46 minutes, 16 seconds, and West longitude 85 degrees, 02 minutes, 34 seconds. Global Positioning System (GPS) placement of the crash site of N220KM was North latitude 30 degrees, 46 minutes, 16 seconds, and West longitude 85 degrees, 2 minutes, 34 seconds. Two witnesses who were located 3/4 mile northwest of the crash site at the time of the accident observed N220KM flying to the northeast at about 10,000 feet. They observed the wings of the aircraft rock back and forth and then the nose of the aircraft tip downward until the aircraft was descending vertically nose down. The engine noise increased from a low roar to a high pitch whine as the aircraft descended. They observed the belly of the aircraft as it descended nose first until ground impact. PERSONNEL INFORMATION Information on the pilot is located in the First Pilot Information Section. AIRCRAFT INFORMATION Information on the aircraft is located in the Aircraft Information section. METEOROLOGICAL INFORMATION Visual meteorological conditions prevailed at the time of the accident. Meteorological information is contained in the Weather Information section. WRECKAGE AND IMPACT INFORMATION The aircraft crashed in a wooded area adjacent to a pasture at the end of Two Trail Road, Grand Ridge, Florida. Examination of the crash site indicated the aircraft struck the limbs on the north and east side of a pine tree and then impacted the ground on the north side of the tree. A 4-inch diameter tree adjacent to the main wreckage was found severed about 1 foot off the ground. The main wreckage was located nose down in a near vertical position with the top of the aircraft pointing toward 060 degrees. The engine and propeller were found at the bottom of a 5-foot impact crater. Debris from the aircraft was located up to 75 feet from the main wreckage. All components of the aircraft necessary for flight were located at the main crash site. Examination of the aircraft wreckage indicated the aircraft had sustained extensive impact damage. All wing ribs and skin had separated from or been crushed into the wing spar leaving the full wing spar on the left and right sides exposed. The spar had a forward bend to it, beginning at the fuselage area and moving outboard on the left and right sides. The cabin area and empennage were completely destroyed. The horizontal stabilizers, elevators, vertical stabilizer, and rudder were found still attached together. Examination of the rudder controls indicated the right rudder cable was complete and still attached at the rudder and at the pedal in the cabin area. The left rudder cable was still attached at the rudder and separated from the rudder pedal and at a point 1 foot aft of the rudder pedal. Separation points were typical of overstress crushing separation. The aileron and elevator control tube systems were identified. Each of these control systems had multiple separation points which were typical of overstress crushing separation. Examination of the engine indicated the propeller had separated from the engine when the propeller shaft separated during ground impact. The shaft separation points were typical of overstress separation. The No. 1 and 3 cylinder heads separated during ground impact and cylinder No. 2 head was partially separated. The No. 4 cylinder was pushed aft. No components had penetrated the engine case and oil was present in the engine and at the crash site. The exhaust pipe system was recovered. It had sustained extensive crush damage. Examination of the propeller indicated each of the propeller blades was free to turn in the propeller hub. Each blade had extensive twisting and bending damage. Each blade was complete and had chordwise scratching on the forward and aft faces. The engine tachometer was located in the wreckage crater. The tachometer recording meter read 387.32 hours. A mark was present on the face of the tachometer at 2,800 rpm. The rpm needle was missing. The engine-driven vacuum pump was located. The drive shaft was not separated. The remainder of the pump sustained impact damage. The directional gyro was found to be reading 030 degrees. The gyro rotor had rotational scarring damage. The turn and bank indicator gyro rotor was located and found to have rotational scarring. About 2 square feet of the cockpit canopy was recovered from the crash site. No evidence of in-flight collision with birds was noted on the canopy, nor were any bird remains found at the crash site. MEDICAL AND PATHOLOGICAL INFORMATION Postmortem examination of the pilot was performed by Dr. Jerry L. Harris, M.D., Associate Medical Examiner, Tallahassee, Florida. The cause of death was determined to be massive trauma due to an airplane crash. No findings which could be considered causal to the accident were noted. Postmortem toxicology testing on specimens obtained from the pilot was performed by Dr. Dennis V. Canfield, Ph.D., Manager Toxicology Laboratory, Federal Aviation Administration, Oklahoma City, Oklahoma. The tests were positive for ethanol, iso- propanol, and 1-butanol in muscle tissue. These findings were attributed to postmortem decay of the toxicology sample. The tests were negative for basic, acidic, and neutral drugs. For additional medical and pathological information see Supplement K and the toxicology report. TESTS AND RESEARCH Recorded radar data from the FAA Jacksonville Air Route Traffic Control Center was studied by the NTSB, Office of Research and Engineering. The radar data along with winds aloft information and engineering data supplied by the aircraft manufacturer for the RV-6 was entered into the NTSB computer. Several computer programs were run to analyze the data and produce output reports of the aircraft's performance. (See Specialist's Report of Investigation Recorded Radar Study.) Review of the radar study output was reviewed by Mr. Richard VanGrunsven, President, Van's Aircraft, Inc., the manufacturer of the RV-6 aircraft kit. He stated that "from my experience, it would seem that during the final minute (approximate) of the flight, the aircraft was not only un-controlled, but that a sub- conscious or accidental pressures might have been applied to the control stick." He further stated that he is not aware of any stability or control characteristic which would cause the flight path described by the recorded radar information. (See letter from Mr. VanGrunsven.) A review of recorded radio communications from the pilot of N220KM was performed by the NTSB, Engineering Services Division. A spectral study of the last seven transmissions from the accident aircraft revealed no usable spectral information or meaningful frequency information. (See Specialist's Report of Investigation Air Traffic Control Tape Study.) Personnel at the aircraft service company at Mobile Regional Airport where the flight last stopped were interviewed. The personnel stated the pilot arrived and requested that the aircraft's fuel tanks be filled. The pilot borrowed a car and went to an unknown fast food restaurant near the airport for lunch. When he returned they talked with him briefly about the aircraft and he then departed. They stated the pilot was "a nice guy" and that he appeared tired and anxious to get home to Pompano Beach, Florida. The personnel stated to Sheriff's Department investigators that the pilot was in good spirits and referred to the RV-6 as his baby. They reported the fuel source was tested in the morning prior to fueling N220KM and no problems were found. (See record of telephone conversation and Sheriff's Department report.) The pilot's wife stated after the accident that the pilot was in good health. He did not smoke and that he would run on a regular basis. He had been in Fort Worth, Texas, receiving McDonnell-Douglas MD-11 flight training for the airline he was employed by as a pilot. He received his MD-11 type rating 4 days before the accident and had completed all training the day before the accident. A friend of the pilot reported to NTSB that she worked with the pilot in the late 1970's. He told her at that time that while flying a Cessna 152 at 13,500 feet in the late 1970's he experienced cramping in his arms and lost feeling. The aircraft began a descent and it was not until 1,000 feet that he regained feeling in his arms and recovered from the descent. She stated she would send a letter to NTSB concerning this incident; however, it was not received by NTSB after several phone calls requesting the letter. (See record of conversation.) Mr. Malcolm Brenner, NTSB, Aviation Human Performance Division, stated that he consulted several medical doctors concerning the above report and that no history of such a response to high altitude flight is known. ADDITIONAL INFORMATION The aircraft wreckage was released on September 2, 1993, to Mr. Kelly Bare, Insurance Adjuster, Florida Air Marine Adjusters, Tampa, Florida.
UNDETERMINED.
Source: NTSB Aviation Accident Database
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