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N7738F accident description

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Tail numberN7738F
Accident dateAugust 20, 1998
Aircraft typeCessna 150F
LocationWilton, AR
Additional details: None

NTSB description

HISTORY OF FLIGHT

On August 20, 1998, at 1259 central daylight time, a Cessna 150F airplane, N7738F, owned and operated by a private individual, was substantially damaged upon impact with terrain during takeoff from a private airstrip near Wilton, Arkansas. The commercial rated pilot was fatally injured, and his passenger sustained serious injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulation (CFR) Part 91 aerial observation flight. The flight was originating at the time of the accident. According to the passenger, the purpose of the flight was to fly to Clarksville, Texas, for "fire patrol."

During a personal interview conducted by the NTSB investigator-in-charge (IIC), a witness, located approximately 328 yards south of the accident site, reported observing the accident aircraft "flying very low, (tree top high)" in a nose high attitude and descending after takeoff from the Garrison's private airstrip. The witness observed the airplane bank left and travel west across Highway 71, then "nose dive and crashed." The witness added that the engine was "running good," but the "engine was not at a high rpm." The witness also stated that the engine was not "missing or sputtering," and it sounded as though "it was in a strain, like a lawn mower in tall grass, pulling down."

A witness, located approximately 100 yards north of the accident site, reported to the NTSB IIC that he observed the airplane flying towards him low over the trees and the engine sounded like it was "back firing." As the airplane turned left, the right wing brushed the tree next to his trailer house, and then nosed over and impacted the ground.

A witness, seated in the front right seat of a parked car, reported to the Arkansas State Police that he "noticed a small airplane appearing into view from behind me and going at an angle to the right and away from me. The plane was flying at a height which appeared to be higher than the length of two telephone poles." The witness stated that the "plane's tail suddenly rose upward and the nose dropped down." Also, the airplane began to turn in a counter-clockwise direction as the nose dropped. The airplane descended straight down and impacted the ground. He further stated that the right door of the airplane was "wide open."

The passenger reported to the Arkansas State Police that the pilot "pulled back [too] hard on the controls causing the airplane to stall."

During a telephone interview conducted by the NTSB IIC, the passenger reported that he met the pilot at the pilot's son's private airstrip, which is located on the south side of Wilton. After arriving at the airstrip, he did not observe the airplane being fueled, nor did he observe the pilot check the performance charts or calculate a weight and balance for the flight.

The passenger further reported that the pilot taxied the airplane to the south end of the airstrip and configured the aircraft with 10 degrees of flaps for a north departure. The passenger stated that the takeoff roll on the grass runway seemed a little long, and the aircraft lifted off after about 1,500 feet. The climb appeared to be sluggish and the stall warning audio began to sound right after lift off. He estimated that they got to a maximum altitude of 150-200 feet agl. He also stated that he has no recollection of how the engine sounded or its power output. The passenger also reported that he could not recall anything else that happened during the flight.

PERSONNEL INFORMATION

The 60-year-old pilot's flight logbook was not located; therefore, total flight time and the date of his last biennial flight review could not be determined. According to the application for the pilot's most recent second class medical certificate, dated July 9, 1994, he had accumulated a total of 900 flight hours, of which 60 hours were in the previous six months. The second class medical certificate stipulated a limitation to wear corrective lenses while operating an aircraft.

The passenger held a student pilot certificate and was actively working towards a private pilot certificate.

AIRCRAFT INFORMATION

The Cessna 150F, serial number 15063838, was equipped with a 100-horsepower Continental O-200-A engine. Maintenance records revealed that the engine was last overhauled on March 19, 1987, at a total engine time of 1,736.8 hours. According to maintenance records, the aircraft's last annual inspection was completed on November 13, 1998, at an aircraft total time of 2,295.19 hours.

Weight and balance calculations were performed using data provided by the manufacturer. The passenger and the pilot's last FAA medical examination provided the weights of the passenger and pilot. An estimate of the airplane's weight at takeoff was 1613.4 pounds, and its estimated weight at the time of the accident was 1,601.4 pounds. According to the manufacturer, the maximum gross weight of the airplane is 1,600 pounds.

The owner/operator reported in the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, that the maximum gross weight of the aircraft was 1,760 pounds. However, according to the aircraft's maintenance records, the last adjustment to the weight and balance was completed on April 16, 1979, and the maximum gross weight remained at 1,600 pounds. On March 1, 1990, droop style wing tips were installed; however, according to the maintenance records, there were no adjustments made to the weight and balance at this time.

The owner's manual for the aircraft states in Section II, Description and Operating Details, page 2-7, TAKE-OFF, FLAP SETTINGS: "Normal and obstacle clearance take-offs are performed with flaps up. The use of 10 degrees flaps will shorten the ground run approximately 10 percent, but this advantage is lost in the climb to a 50-foot obstacle. Therefore the use of 10 degrees flap is reserved for minimum ground runs or for take-off from soft or rough fields with no obstacles ahead. If 10 degrees of flaps are used in ground runs, it is preferable to leave them extended rather than retract them in the climb to the obstacle. The exception to this rule would be in a high altitude take-off in hot weather where climb would be marginal with flaps 10 degrees. Flap deflections of 30 degrees and 40 degrees are not recommended at any time for take-off."

A review of the airframe and engine records by the NTSB IIC did not reveal evidence of any anomalies or uncorrected maintenance defects.

METEOROLOGICAL INFORMATION

A local law enforcement official estimated the temperature to be above 95 degrees, with the wind out of the east at about 5 knots.

The passenger estimated the temperature to be about 100-105 degrees, with the wind out of the north at less than 5 knots.

At 1253, 6 minutes prior to the accident, the wind at the Texarkana Regional Webb Airport, located about 19 miles south-southeast of the accident site, was from 080 degrees at 9 knots, and the temperature was 91 degrees F.

Calculations by the NTSB IIC indicate the density altitude was 2,958 feet.

AERODROME INFORMATION

The Garrison private airstrip has a grass runway 3,200 feet in length, which is oriented 35/17. Aircraft are fueled from a 500-gallon storage tank, which is labeled "Av Gas 100LL."

On August 3, 1998, Weldon Garrison purchased 500 gallons of 100 low lead aviation fuel from the Miller-Claborn Oil Distributing Company, Inc., of Texarkana, Arkansas. A local distributor picked up the 500 gallons of aviation fuel from the Miller-Claborn Oil Distributing Company and delivered it to the Garrison airstrip and unloaded it into the fuel storage tank.

The Garrison's storage tank record showed 7 gallons of fuel was dispensed on August 19, 1998, and 16 gallons on August 20, 1998. According to the pilot's son (airstrip owner), his father had fueled and flown his brother's Cessna 172 (N1834B) on August 19th. There were no reported problems with the Cessna 172's fuel. On the day of the accident, the pilot fueled N7738F (accident airplane) with 16 gallons.

On September 8, 1998, the owner of the airstrip reported to the Ashdown Police Department that the fuel in the storage tank appeared to be contaminated. On September 9, 1998, representatives from the Ashdown Police Department and the Arkansas Bureau of Standards collected samples from the storage tank and from the airstrip owner's Cessna 172, N2776U (aircraft was fueled prior to the August 3rd fuel delivery), for laboratory analysis at the Arkansas Bureau of Standards, Petroleum Division in Little Rock, Arkansas. See the Tests and Research section of this report for further information on the fuel and test results.

WRECKAGE IMPACT INFORMATION

The aircraft came to rest in the backyard of a private residence at 585 Main Street/Highway 71. Examination of the accident site revealed that the airplane initially impacted the ground on a measured magnetic heading of 160 degrees with a second impact heading of 130 degrees. The aircraft came to rest on its nose and right wing with the empennage resting up against a tree, 13 feet 6 inches from the second impact point, on a magnetic heading of 090 degrees.

Examination of the airplane revealed that the engine was partially separated from the fuselage, and the firewall was displaced aft. The tail was buckled aft of the cabin area, and both wings exhibited damage to the outboard leading edges and tips. The flap indicator located in the cockpit showed a flap setting of less than 10 degrees. However, the flap jackscrew was measured to be about 5.0 inches, which equates to the flaps being extended 30 degrees. Continuity was established from the cockpit controls to all flight control surfaces.

The engine's crankshaft was rotated by hand and continuity was confirmed to all cylinders and to the rear of the engine. The impulse coupling on the magneto snapped at top dead center on the number one cylinder. Both magnetos sparked at all terminals when hand rotated. All spark plugs were found to have light wear and light deposits in the electrode areas, and the top #1 and #3 spark plugs were oily.

The carburetor was disassembled and found to be equipped with metal floats and a two-piece venturi. The bowl contained no debris, and the accelerator pump expelled fuel when the throttle arm was moved. The fuel system was found breached, and when the aircraft was moved, clear fuel was observed escaping from the fractured fuel lines.

The propeller remained attached to the crankshaft. One propeller blade exhibited slight "S" bending with chordwise scratching. The other blade did not exhibit any damage.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy and toxicological tests of the pilot were requested and performed. Toxicology tests were performed by the Civil Aeromedical Institute (CAMI), of Oklahoma City, Oklahoma. Toxicology tests for carbon monoxide, cyanide, volatiles (alcohol), and drugs were negative. The autopsy was performed at the Arkansas State Crime Laboratory, in Little Rock, Arkansas. According to the autopsy report, the cause of death was attributed to multiple injuries with severe occlusive coronary artery disease. Other significant findings included atherosclerotic cardiovascular disease, and a pinpoint lumen of the left anterior descending coronary artery. Although the autopsy noted severe coronary disease, there were no areas of complete blockage of the coronary arteries, and the pathologist specifically concluded there was "no evidence of acute myocardial infarction (heart attack)."

SURVIVAL ASPECTS

The 1966 Cessna model 150F airplane was not equipped with shoulder harnesses for either occupant.

TESTS AND RESEARCH

The Arkansas Bureau of Standards laboratory test results revealed that all fuel samples "failed distillation temperature requirements for aviation gasoline as listed in the American Society for Testing and Materials (ASTM) standards manual (D910). Additionally, the vapor pressure tested below minimum ASTM requirements." See the enclosed Arkansas Bureau of Standards Laboratory report for further information.

The Ashdown Police Department also collected samples from the storage tank for laboratory analysis at the Sorrells Research Laboratory, in Little Rock. The samples that were received had a slight yellow color. The samples "matched aviation gasoline except for scum content (e.g., tank bottoms, higher-boiling residue) ... Among the high-boiling residues, certain plasticisers are identifiable." See the enclosed Sorrells Research Laboratory report for further information.

Miller-Claborn had fuel samples collected from their aviation fuel storage tank and the Garrison storage tank for laboratory analysis at the EarthNet Laboratories, Inc., in Ruston, Louisiana. All samples submitted "contained less than 1 ppm moisture, Iron, Magnesium, and Zinc levels that were non-detectable, and no visual growth contamination." The "analysis for metals (presence or absence of rust or metal degradation of storage tank) samples were filtered for suspended materials or fine particulates." None were found. See the enclosed EarthNet Laboratories report for further information.

Law enforcement officers from the Ashdown Police Department, who responded to the accident site, reported observing fuel leaking from both wings, and "the fuel was a brownish color and was very foamy in appearance. It appeared to be gasoline fuel or auto type gasoline."

Personnel of Dawson Aircraft of Clinton, Arkansas, recovered the aircraft. They reported to the NTSB IIC that they had drained the fuel from both wing tanks prior to recovering the aircraft. The fuel was blue in color.

On September 24, 1998, the NTSB IIC visually inspected the fuel storage tank at the Garrison airstrip and the aviation fuel storage tank at Miller-Claborn. The fuel in the Garrison storage tank had a straw color tint. The fuel in the Miller-Claborn storage tank was blue in color.

On September 25, 1998, the NTSB IIC drained the accident airplane's wing fuel tanks and collected about 2 ounces of residual fuel. The fuel was blue in color. Additionally, the IIC observed that both of the tanks were placarded "approved fuel, UNLEADED AUTOMOTIVE GASOLINE, 87 minimum antiknock index per ASTM spec D-439."

ADDITIONAL DATA

The aircraft wreckage was released to the owner's representative on August 26, 1998.

(c) 2009-2011 Lee C. Baker. For informational purposes only.