NTSB Factual Report

HISTORY OF FLIGHT

On September 27, 2006, at 1620 eastern daylight time, a Beech S35, N5852S, was destroyed by a post crash fire when it impacted terrain after striking trees during the initial climb from Lake City Airpark (FL27), Lake City, Florida. The certificated airline transport pilot was fatally injured. Visual meteorological conditions prevailed and no flight plan was filed for the local flight conducted under 14 Code of Federal Regulations (CFR) Part 91.

According to witness statements, because of low compression, two of the accident airplane's engine cylinders were treated the evening before with a combination of hydraulic fluid and lacquer thinner for "stuck valves." The combination of lacquer thinner and hydraulic fluid was introduced into the cylinders through the upper spark plug holes of the No. 2 and No. 3 cylinders and allowed to sit overnight.

The next day, the pilot was observed taxiing the airplane to runway 23 and conducting a lengthy runup. The airplane was then observed airborne, climbing at a steep angle. During the climb, the airplane "tilted to the right," and struck trees, prior to going "out of control" and impacting the ground. Witnesses heard a loud "bang" and observed a postcrash fire.

According to friends and relatives of the pilot, they believed that there was no intention of flight and stated that the pilot had advised them that "he was not going to fly." They also stated that the airplane required an annual inspection and that the pilot had recently experienced health problems, rendering him ineligible for a Federal Aviation Administration (FAA) medical certificate.

The accident occurred during the hours of daylight. The wreckage was located at 30 degrees, 02.590 minutes north latitude, 82 degrees, 36.247 minutes west longitude, at an elevation of 120 feet above mean sea level (msl).

PERSONNEL INFORMATION

According to FAA records, the 81-year-old pilot held an airline transport pilot certificate with multiple ratings including airplane single-engine-land. On his most recent FAA third-class medical certificate, dated May 24, 2003, he reported a total flight experience of 26,000 flight hours.

AIRCRAFT INFORMATION

According to maintenance records, the airplane was manufactured in 1965. The engine was rebuilt by the manufacturer on June 12, 1996, and was installed in the aircraft on July 17, 1996. At the time of the accident it had accrued approximately 215 hours of operation. The airplane received its last annual inspection on April 21, 2005, and at the time of the inspection, had 4,978.92 hours of operation.

METEOROLOGICAL INFORMATION

A weather observation taken about 36 minutes after the accident at Lake City Municipal Airport (LCQ), Lake City, Florida, located approximately 9 nautical miles north of the accident site, included, calm wind, visibility 10 miles, a few clouds at 7,000 feet, temperature 64 degrees Fahrenheit, dew point 57 degrees Fahrenheit, and an altimeter setting of 29.94 inches of mercury.

AIRPORT INFORMATION

Lake City Airpark was a private use airport. It had one runway, oriented in a 05/23 configuration. The runway was turf-covered, in good condition, and was 3,175 feet long by 150 feet wide, with a 1,340 foot displaced threshold.

WRECKAGE AND IMPACT INFORMATION

Examination of runway 23 revealed three tire tracks in the turf-covered runway, which correlated to the landing gear footprint of the Beech S35. These tire tracks started near the beginning of the runway and immediately began to arc towards the left side, where they exited the maintained portion of the runway onto the surrounding grass, continuing for 1,247 feet. At that point, the center of the three tire tracks was no longer evident.

Approximately 58 feet later, the remaining two tire tracks disappeared. About 233 feet farther on, broken tree branches and the right wingtip navigational light lens were discovered at the edge of a small cluster of oak trees. Multiple small pieces of fiberglass and Plexiglas from the right tip tank were also discovered, spread throughout the trees.

The airplane struck the trees at an approximate height of 69 feet above ground level, 18 degrees left of the published runway heading. It then traveled another 245 feet, impacted the ground in a 58-degree nose-down attitude, and then came to rest right side up on a magnetic heading of 109 degrees, 37 feet west, southwest of its initial ground impact point.

The main wreckage displayed varying degrees of impact damage, and a postcrash fire consumed the majority of the cockpit and cabin. The left and right wings, along with all the associated flight control surfaces displayed differing degrees of damage. Both wing tanks had been breached and the bladders had been destroyed by fire. The left and right ruddervators were intact and undamaged and the ruddervator differential mechanism was intact and functional. The flap actuators correlated to the flaps up position, and the elevator trim correlated to approximately neutral. All major components of the airplane were accounted for at the accident site, and flight control continuity was confirmed from the ailerons to the surviving portions of the control column, and from the ruddervators to the approximate location of where the cabin was located.

Examination of the remains of the cockpit controls revealed that the throttle control was full in, the cowl flaps were open, and the landing gear selector switch was in the landing gear down position.

Examination of the propeller revealed that it had separated from the engine at the crankshaft flange. The propeller blades displayed chordwise scratching, blade face polishing, and evidence of twisting towards low pitch.

Examination of the engine revealed no evidence of preimpact malfunction and had remained intact, with the exception of the propeller, starter, and alternator, which had separated during the impact sequence. Postcrash fire and impact damage existed in all areas. The crankshaft displayed a 45-degree shear face, which existed over one-third of the forward portion of the crankshaft flange. The left side cylinder valve covers were melted and heat discoloration was present on all three left side cylinders. The top ignition harness was charred, and the left side intake pipes were partially melted. The propeller governor was in the full advance position and the mixture control was in the mid range position. The throttle control interconnect was partially melted and the throttle valve was in the closed position.

The oil filter exhibited signs of heat discoloration and impact damage. It was opened and the filter element was charred. No metal particles were discovered.

The upper spark plugs were removed along with the valve covers, oil pump cover, and fuel pump. The crankshaft was rotated by hand and continuity was confirmed to all of the cylinders and to the rear of the engine, including the oil pump. The No. 2 exhaust valve was observed to be sticking in the open position. Thumb compression was confirmed on cylinders No. 1, 3, 4, and 5. Air was leaking around the exhaust valve in the No. 2 cylinder and past the piston rings on the No. 6 cylinder. Both the No. 2 and No. 6 cylinders exhibited heavy fire damage and heat discoloration.

The cylinders were borescoped and all cylinder domes and piston heads appeared normal; however, the No. 2 cylinder exhaust valve was in the open position.

The spark plugs appeared normal with light gray deposits in the electrode areas.

Both magnetos exhibited soot and heat discoloration. The impulse couplings snapped at top dead center on the number one cylinder when the crankshaft was rotated. The right magneto produced spark at all towers. The left magneto would rotate, however; it would not produce spark and when disassembled exhibited partial melting of its interior components.

Examination of the engine's fuel distribution system revealed that the fuel-metering unit was heavily fire damaged and was partially melted. The fuel screen was clean, clear, dry, and exhibited heat discoloration.

The fuel injection nozzles were coated externally with soot. Fuel injection nozzles No. 1, 3, and 5 were partly obstructed with soot. The remainder of the fuel injection nozzles were clear.

The fuel pump was still attached to the engine. All of its lines remained connected with the exception of the fuel inlet line, which was impact damaged and had separated. The drive coupling was intact and undamaged, however; the drive shaft would not rotate. The unit was disassembled and the interior exhibited heat discoloration and was dry. No internal damage was observed.

The fuel manifold was covered with soot and was discolored by heat. The unit was disassembled and the diaphragm and spring were undamaged. The fuel screen was clean of any sediment and debris and no discoloration was present.

MEDICAL AND PATHOLOGICAL INFORMATION

A postmortem examination was performed on the pilot by the State of Florida's Office of the Medical Examiner.

Toxicological testing of the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma.

The pilot's forensic toxicology report indicated:

">> VERAPAMIL detected in Blood

>> VERAPAMIL detected in urine

>> NORVERAPAMIL detected in Blood

>> NORVERAPAMIL present in Urine"

According to medical records maintained by the FAA Aerospace Medical Certification Division, the pilot had experienced the passing of a kidney stone in 1982 with no apparent recurrence. He also had glaucoma and cataracts but both were resolved with cataract surgery. He had diabetes and high blood pressure, which were being controlled through the use of oral medications.

According to the pilot's personal medical records, since the time of his most recent FAA third-class medical certificate in 2003, a number of medical diagnoses had been documented. These included the finding of some previous asymptomatic strokes, a number of neurologic symptoms, and a complete occlusion of both main (carotid) arteries in his neck. Additionally, he was diagnosed with significant coronary artery disease, severe osteoarthritis of the knee, and a pulmonary embolus following a right knee replacement in August 2005.

The personal medical records also documented a number of additional medical procedures and treatments, including surgery to open one of the pilot's carotid arteries, three stents placed to open his coronary arteries, and the use of a blood thinner (warfarin) to reduce the likelihood of another pulmonary embolus.

A study of his heart function approximately six months prior to the accident suggested that the coronary artery stents were functioning. He was having no further neurological events, and had no indication of additional pulmonary embolus. Another study performed approximately two months prior to the accident demonstrated that the one carotid artery that had been surgically opened had remained open, and that the one that had been left alone had remained totally clogged.

Three months prior to the accident, his personal medical records documented his only complaint as persistent knee pain, and a blood test approximately 3 weeks prior to the accident showed that his blood thinner (warfarin) was reducing the clotting of his blood.

According to family members, the family had a history of strokes and both the pilot's parents had died from them. The pilot also would bruise and bleed easily and his doctor would check him weekly.

ADDITIONAL INFORMATION

According to Teledyne Continental Motors Service Information Letter SIL99-2B, there are many fuel and oil additives and/or concentrates, which were formulated primarily for automotive or industrial use. It goes on to advise that most additives and concentrates are not compatible with air-cooled engines and with few exceptions they "do not recommend the use of additives or concentrates" in any of their engines and recommend only the use of fuels and lubricants that are listed in SIL99-2B. A review of SIL99-2B revealed that neither hydraulic fluid nor lacquer thinner was listed.

According to the Sky Ranch Engineering Manual, Chapter 2 (Engine Inspection), in the event of a stuck valve you should not use "Marvel Mystery Oil or other solvents" to un-stick a valve. The solvents may un-stick a valve "in time" but not immediately and eventually the valve may unstick, but not before damage to the camshaft lobes has occurred. It goes on to say that solvent treatments may dissolve outer deposit layers in the guide boss and temporarily un-stick a valve, however, the remaining deposits may "push" the valve over to the opposite side of the guide and cause rapid and uneven guide wear.

Additionally, it states that "catastrophic engine damage" can occur and that "tremendous valve train forces develop as the camshaft lobe tries to force the valve open and since normally the highest loaded surfaces in the engine are the camshaft follower and lobe, additional loading may induce failure."

NTSB Probable Cause

A loss of control during an unintentional takeoff for an undetermined reason.