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N6425T accident description

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Crash location Unknown
Nearest city Collinsville, OK
36.364538°N, 95.838877°W

Tail number N6425T
Accident date 19 Aug 2000
Aircraft type Cessna 150
Additional details: None

NTSB description


0n August 19, 2000, at 1509 central daylight time, a Cessna 150 single-engine airplane, N6425T, was destroyed when it impacted terrain in an uncontrolled descent following takeoff from the Sky Haven Airpark, a private grass airstrip near Collinsville, Oklahoma. The airplane was owned and operated by the pilot under 14 Code of Federal Regulations Part 91. The private pilot received fatal injuries. Visual meteorological conditions prevailed for the flight to Tulsa, Oklahoma, and a flight plan was not filed. The flight was originating at the time of the accident.

The pilot of another Cessna 150 (N2224T) reported that he and the pilot of N6425T agreed to fly their airplanes, respectively, from the Richard Lloyd Jones Jr Airport, Tulsa, Oklahoma, to the Sky Haven Airpark. The pilot of N2224T reported no discrepancies were found with N6425T during the preflight inspections. The pilot of N6425T departed Tulsa at 1230, and flew to the Riggs Airport (a private grass airstrip located southeast of Sky Haven Airpark). The pilot of N2224T departed Tulsa about 10-15 minutes later and rendezvoused with N6425T. Subsequently, the pilots flew their airplanes over Lake Oolagah for approximately one hour, landed and departed the Avian Estates Airstrip, and subsequently landed their airplanes at Sky Haven Airpark. The accumulated flight time for the day was estimated at 2 hours.

Witnesses reported that about 20-30 minutes prior to the accident, the two Cessna 150 airplanes (N6425T and N2224T) landed at Sky Haven Airpark, and each pilot exited their respective aircraft. The pilots visited with a commercial pilot (one of the witnesses) at his hangar, and subsequently planned to depart the airstrip and return to the Richard Lloyd Jones Jr Airport near Tulsa, Oklahoma. The pilot of the accident airplane mentioned that he wanted to take some pictures of an airstrip lot that one of his friends had purchased.

From his hangar which faced east, the commercial pilot observed the two airplanes taxi to the north end of the airstrip. The accident airplane was number one for departure. The witness reported that the pilot applied full power and the airplane "accelerated normally down the runway. He broke ground at just past my hangar, climbed to only 50 feet and made a hard left turn 35-40 degree bank and at a slow airspeed. He allowed the aircraft to climb at a high angle of attack Vx to 150-200 feet and about 1/4 mile east of runway. He made another steep left turn 45-degree bank or greater, at a slow speed. Now [after establishing the airplane] on a short downwind 200-250 feet, he made one wave of his wings steep bank angle 45-degrees or more. He then made another steep left turn 45-degrees or more. Heading 270 degrees due west, the pilot over corrected for his turn using rudder to align the aircraft with the desired course. Immediately after completing the turn to the west he made another wave of his wings 45-degree bank or more. Making one wave to the right then left. At this point the left wing stalled. The aircraft nosed down and started a spin to the left. It made almost one complete revolution before impacting the ground in a nose down attitude 60-70 degrees." The engine sounds "appeared normal making power to impact."

A second witness, located on the west side of the airstrip, observed the airplane about 50-70 feet above the ground in a "hard (about 50-70 degree pitch downward) nose-down attitude." The witness saw the airplane hit the ground.

Another witness, located west of the Sky Harbor Airpark, observed the airplane "banking right to left several times." This witness did not observe the impact.

The pilot of N2224T, reported that he was number two for departure from Sky Haven Airpark, and that he observed the takeoff of N6425T. After approximately 800-900 feet of ground roll, the airplane (N6425T) began climbing at "maximum performance. At approximately 130-150 feet agl, [the airplane] banked to the left and continued for 180 degree turn."


The pilot held a private pilot certificate with an airplane single-engine land rating, which was issued on February 26, 1982. His most recent third class medical certificate was issued on July 20, 1999, with the limitation that he must have glasses available for near vision while acting as a pilot.

According to the available pilot flight logbooks, from November 1981, through January 1985, he had accumulated 515.3 total flying hours, of which 71.6 hours were flown in a Cessna 150 airplane. Acquaintances estimated that from 1986, through 1991, the pilot flew about 20 hours. A logbook entry for May 1993, recorded 5.2 flight hours. Acquaintances stated that after 1993, the pilot was inactive for 5-6 years. On the pilot's last FAA medical application, he indicated that he had accumulated 1,200 hours of total flight time.

Using aircraft flight log entries for July 1999, through July 2000, and personal knowledge, acquaintances estimated that the pilot had accumulated 150 total flying hours in N6425T within the previous 12 months. They also estimated that through his years of flying, the pilot had accumulated 2,350 total flying hours, of which 1,000 flight hours had not been logged.


The Cessna 150 aircraft, N6425T, serial number (S/N) 17825, was issued an airworthiness certificate on February 24, 1960. The two-seat, single-engine airplane was equipped with a Continental O-200-A four cylinder reciprocating engine (S/N 64244-6-A), rated at 100 horsepower. The airplane underwent its last annual inspection on August 16, 2000, at an aircraft total time of 2,606.0 flight hours. Based on the tachometer reading (2,611.74 hours) at the accident site, the airplane had flown 5.74 hours since the last annual inspection. The pilot was the registered owner of the airplane since August 16, 1999.

Examination of the engine's maintenance records revealed that the engine had been overhauled on December 27, 1969, and was reinstalled on the airplane on February 4, 1970, at a tachometer time of 1,693 hours. In August 1997, a single piece venturi and metal floats were installed in the carburetor. In February 1999, the #1 cylinder valves and springs were replaced, as well as the piston rings on the #1 piston. Additionally, both magnetos were disassembled, inspected, the bearings greased, EGAP set, and reassembled.

According to the August 16, 2000, annual endorsement, the #4 cylinder was removed "due to low compression." The valves and their seats were ground, the cylinder was honed, and new piston rings were installed. According to the endorsement, the cylinder was reassembled and reinstalled on the engine using a new gasket set. The endorsement also indicated that all 8 spark plugs were replaced with new spark plugs, and the carburetor had been removed, overhauled, and reinstalled on the engine.

On August 15, 1999, the aircraft was re-weighed at a new basic empty weight of 1,054 pounds, a center of gravity (CG) of 31.3 inches aft of datum, and a useful load of 446 pounds.

The weight and balance was calculated by the NTSB investigator-in-charge (IIC) and an aircraft manufacturer's representative for the takeoff at Collinsville. The pilot's weight was taken from his last medical certificate, and an estimated baggage weight of 10 pounds was used. Airport personnel and acquaintances of the pilot reported that the airplane departed Tulsa with full fuel (22.5 gallons) and had flown 2 hours on the day of the accident. According to the manufacturer, the estimated fuel consumption for the 2 hour flight was 9 gallons. Therefore, the airplane departed Collinsville with an estimated 13.5 gallons (87 pounds) of fuel. According to the flight manual, the maximum allowable gross weight of the airplane is 1,500 pounds and the allowable CG range is 33.1 inches to 36.0 inches aft of datum. Considering the above data, at the time of the accident, the estimated takeoff weight would have been 1,374 pounds, and the CG would have been 33.5 inches aft of datum.

One of the witnesses reported that he had flown with the pilot on August 17, 2000, for approximately 2 hours following the last annual inspection. No discrepancies were noted.


The pilot of N2224T reported the weather as "hot, sunny, around 100-102 degrees Fahrenheit." At 1452, the Tulsa International Airport's weather observation facility (located 13 miles south of Sky Haven Airpark) reported the wind from 180 degrees at 11 knots, gusting 16 knots. The temperature was reported as 97 degrees Fahrenheit.

At 1453, the Richard Lloyd Jones Jr Airport's weather observation facility (located 22 miles south of Sky Haven Airpark), reported the wind from 180 degrees at 10 knots. The temperature was reported at 36 degrees Celcius (96.8 degrees Fahrenheit).

Using the aforementioned weather data and the Sky Haven Airpark elevation (675 feet msl), the density altitude at the time of the accident was calculated to be 3,272 feet by an NTSB investigator.


Sky Haven Airpark (latitude 36 degrees 25.97 minutes North; longitude 095 degrees 54.17 minutes West) is owned and operated by a private individual. The non-towered airstrip is located approximately 13 miles north of Tulsa, Oklahoma. The grass airstrip has a north/south 4,400-foot runway. The landing width was a measured 78-foot width with the runway edge sloped for water drainage. The trees had been removed from the approach path of the south runway, and power lines across the departure end were marked with colored balls.


The wreckage was located 156 feet east of the runway center and 910 feet beyond the south runway threshold. The wreckage distribution path extended for 117 feet on a measured magnetic heading of 245 degrees. The initial ground scar measurements were consistent with the length of the right wing and the engine cowling. Portions of yellow paint, airplane skin, the nose landing gear, the right wing green navigation lens, and the propeller were found in the vicinity of the initial ground scar. The airplane came to rest upright 84 feet beyond the initial ground scar, and on a measured magnetic heading of 360 degrees.

Both wings remained attached to the fuselage. The integrity of the cockpit was compromised with the roof crushed aft and inward. The empennage was found separated aft of the baggage compartment. The outboard 9 feet of the right wing leading edge was crushed upward and aft. The right wing tip skin was wrinkled and crushed. The left wing, outboard of the landing light, was wrinkled and crushed.

Flight control continuity was confirmed from the cockpit to the flight control surfaces. The manual flap extension handle was found at the 10-degree flap notch. According to the manufacturer representative, the trim measurement of "1.2 inches equates to 5 degrees tab down (nose up) for the elevator trim."

The fuel system was not compromised. The right fuel cap was vented and the left fuel cap was non-vented. Local authorities found fuel leaking from the right wing fuel vent. The fuel selector was found in the "ON" position, and fuel (blue coloration) was found in the fuel tanks, fuel lines, gascolator, and carburetor. No debris was found on the gascolator or carburetor filters, respectively. The fuel primer was in and locked.

The propeller blades were found bent and twisted. The propeller separation at the crankshaft propeller flange was consistent with a torsional overload separation.

The engine crankshaft was rotated manually and continuity was confirmed with compression and valve action noted on all 4 cylinders. Both magnetos produced spark on all posts when the engine crankshaft was rotated.


An autopsy on the pilot was performed by the Oklahoma Medical Examiner's Office, in Tulsa, Oklahoma. The FAA Civil Aeromedical Institute's (CAMI) Forensic Toxicological and Accident Research Center at Oklahoma City, Oklahoma, examined specimens taken by the medical examiner. The CAMI toxicological findings were positive for 0.079 (ug/ml, ug/g) chlorpheniramine and 0.13 (ug/ml, ug/g) trazodone in the pilot's blood. Non-quantified amounts of chlorpheniramine, trazodone, ephedrine, and pseudoephedrine were detected in the pilot's urine.

According to Dr. Canfield at CAMI, "chlorpheniramine is an antihistamine used in symptomatic management of allergic symptoms and may have sedative effects. Ephedrine and pseudoephedrine are used in the management of upper respiratory symptoms. Trazodone is an antidepressant, which would have precluded medical certification" of the pilot had it been reported. FAA review of the pilot's past medical applications indicated that the "airman failed to report this medication" to the FAA.


The airplane was released to the owner's estate.

(c) 2009-2018 Lee C. Baker / Crosswind Software, LLC. For informational purposes only.