NTSB Factual Report

HISTORY OF FLIGHT

On July 28, 1997, approximately 1215 central daylight time, an Ayres S2R-T15 agricultural airplane, N3069K, was destroyed when it collided with trees and terrain while in cruise flight near Oakridge, Louisiana. The instrument rated commercial pilot, the sole occupant, was fatally injured. The airplane was registered to Wilmot Flying Service Inc., of Wilmot, Arkansas, and operated by Arkla Flying Service Inc., of Mer Rouge, Louisiana. Visual meteorological conditions prevailed and no flight plan was filed for the Title 14 CFR Part 91 positioning flight. The flight departed Northeast Louisiana Flyers Airport (5F6), Mer Rouge, Louisiana, about 1215 and was en route on a 17 nautical mile flight to the John H. Hooks Jr. Memorial Airport (M79), Rayville, Louisiana.

According to the chief pilot, the airplane departed about 1200 on the planned 15 minute flight to Rayville to position the airplane for an aerial application job. He reported that the airplane did not arrive at the intended destination. Subsequently, the company and the Sheriff department initiated a coordinated air and ground search. The wreckage was located amidst a 100 yard wide line of mature trees and dense vegetation that was oriented east/west. All adjacent quadrants of the tree line were bordered by acres of open cultivated fields.

PERSONNEL INFORMATION

According to information provided by the operator and FAA records, the 33 year old pilot had accumulated about 6,200 hours of total flight time, of which 850 hours were flown in the Ayers SR2-T15 airplane. He had flown about 140 hours in the last 30 days, and about 8 hours in the last 24 hours prior to the accident.

On the morning of the accident, the pilot reported for work at 0530. He assisted with some aircraft maintenance until about 1000. Approximately 1050, he flew the airplane on an aerial application job to apply fertilizer to a local field. After completing the flight, he had the airplane fueled and called ahead to his next job located in Rayville.

AIRCRAFT INFORMATION

The 1991 Ayers model SR2-T15, serial number T27-028, was purchased by the operator in June of 1991. Operator's records showed that the airframe had about 4,153 hours total time since new. According to entries in the records, the last annual inspection was completed on May 5, 1997, at a total time of 4088.7 hours.

The restricted category airplane was equipped with a Pratt & Whitney PT6A-34 engine, manufactured in December of 1976. Operator's records showed that the engine's total time since new was about 12,255.4 hours, and its last major overhaul was completed in January of 1993. The engine's time since major overhaul was about 4,146 hours at the time of the accident.

No anomalies were found in the maintenance records provided by the operator.

WRECKAGE INFORMATION

The wreckage distribution, including ground and tree scars, encompassed an area approximately 390 feet long and 100 feet wide. The center line of the energy path was oriented on an approximate heading of 169 degrees magnetic. Evidence along the flight path indicated that the airplane impacted the mature trees perpendicular to the tree line and descended through the trees approximately 250 feet until coming to rest on the ground.

Examination of the accident site revealed that a post impact fire consumed the fuselage and wings. The left wing main spar was bent aft approximately 90 degrees. The right wing main spar had indentations along the entire span that corresponded to tree impacts. The turbine engine was found separated from the airframe mounts with the case completely split around the circumference of the "C" flange (the power turbine section and the compressor turbine section were separated). The forward case section of the engine, including the exhaust duct, showed torsional twisting in the opposite direction of propeller rotation.

An 8 inch diameter live willow branch was found severed with 2 additional deep cuts along its length. Both the severed section of the branch, and the cuts displayed black paint transfers corresponding to the black paint found on the blade faces of the propellers.

The propeller hub assembly was found completely separated from its mounting flange. The inner portion of the flange showed torsion at the separation point. The oil pressure actuated pitch change piston assembly was found separated from the hub. All of the three metal propeller blades were found attached to the hub within their respective blade grips. One blade displayed "S" bending and twisting forward from about 3 inches outboard of the root along its entire span toward its tip. This blade had chordwise leading edge abrasions along its span and was fractured at the tip. The second blade displayed "S" bending and twisting forward from about 3 inches outboard of the root along its span. This blade was fractured at mid-span. The third blade displayed twisting forward and had chordwise abrasions along its leading edge and was fractured at the tip.

Flight control continuity to the wing flight control surfaces could not be established due to the post impact fire, however, tree strikes along the energy path corresponded to the measured span of the wings, and the strikes were about the same height on each side of the energy path. Control continuity from the aft portion of the fuselage to the rudder and elevator flight control surfaces was established. Flight control cables and tubes in the cockpit area and outboard toward the wings were found completely embedded in molten residues from the post impact fire.

A pipe wrench, about 12 inches long, was found in the molten slag adjacent to where the elevator control push tube attaches to its bell crank.

MEDICAL AND PATHOLOGICAL INFORMATION

The pilot held a valid second class medical certificate, issued March 3, 1997. The certificate stipulated a limitation to wear corrective lenses when operating and aircraft. Information annotated in the FAA's historical medical certification system, showed that the pilot had been admitted to a hospital for "heart or vascular" reasons. A pathology code of "1462" was also annotated in the system. According to the FAA regional flight medicine office, the pathology code indicated a past event(s) of "Tachycardia."

An autopsy was performed on the pilot by Mississippi State Medical Examiner's Office, Pearl, Mississippi, on July 24, 1997. The cause of death annotated on the report was "Smoke Inhalation." A notation affixed to the report stated that there was evidence of the "presence of hypertensive heart disease of mild intensity." No conclusions could be derived as to whether or not a cardiac event could have contributed to the accident.

Toxicological tests were performed by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma. The tests were negative.

FIRE

A post impact fire consumed the fuselage and both wings. No evidence of an in-flight fire was found.

SURVIVAL ASPECTS

The pilot's "5 point" restraining harness buckle was found locked. The restraint attachment points were found intact. The airframe "roll cage" assembly was structurally intact but severely scorched. There was no evidence of an attempted egress. The pilot was wearing a flight helmet.

TESTS AND RESEARCH

In an interview with the NTSB investigator-in-charge, one of the operator's maintenance workers, stated that he thought that he recalled seeing a pipe wrench in a storage compartment on the aircraft. According to the manufacturer, this storage compartment is located behind the cockpit, approximately above were the elevator control tube attaches to the bellcrank in the empennage. It is accessed by a door on the outside of the fuselage. The inner perimeter of the storage area is not completely closed off to the interior of the empennage.

As previously stated, a pipe wrench was found in the slag, about where the elevator control tube attached to the bell crank assembly. Also, mostly all of the inner perimeter of the storage compartment, and its surrounding structure was consumed by the post impact fire.

ADDITIONAL INFORMATION

Three individuals who worked with the pilot were interviewed and provided statements to the investigator-in-charge regarding his daily habits. All three reported that he was always a "safe" and "consciencious" pilot and was always professional. They also stated that they would sometimes observe the pilot "fall asleep" while sitting upright in a room full of people having conversation. The pilot's employer also stated that they had observed the pilot "falling asleep" while sitting down. No medical records were found that indicated that the pilot had a sleeping disorder.

A fellow worker and friend of the pilot reported that he had spoken to him on the morning of the accident. He stated that the pilot was in good spirits and was looking forward to getting together later in the day.

The wreckage was released to the owner at the conclusion of the field portion of the investigation.

NTSB Probable Cause

The pilot's failure to maintain clearance for undetermined reasons.