Aviation Accident Summaries

Aviation Accident Summary LAX03LA197

Porterville, CA, USA

Aircraft #1

N9017N

Bell 47-G4

Analysis

While en route to a field for an aerial pesticide application, the helicopter pitched nose down and impacted the ground. Two roads ran perpendicular to the accident site; one ran east/west, and the other ran north/south. The pilot departed from a service truck in a southwest direction. The destination field was 2 miles southwest of the service truck. As the pilot crossed the east/west road, he made a wide, left turn, traveling northbound. At the intersection of the two roads, the helicopter maneuvered up and over power lines that were parallel to the east/west road. The helicopter turned left about 90 degrees (west), followed by another left turn of 90 degrees (south). The nose suddenly pitched down, and the helicopter impacted the ground. The wreckage site was 1/2 block north from the intersection of the two roads. Post examination of the airframe and engine did not reveal any preimpact anomalies.

Factual Information

HISTORY OF FLIGHT On June 13, 2003, at 0956 Pacific daylight time, a Bell 47-G4 restricted category helicopter, N9017N, impacted terrain during an aerial pesticide application near Porterville, California. Harvest Enterprises was operating the helicopter under the provisions of 14 CFR Part 137. The commercial pilot, the sole occupant, sustained fatal injuries; the helicopter was destroyed. The local flight departed a truck platform about 1 minute prior to the accident. Day visual meteorological conditions prevailed, and no flight plan had been filed. The crew boss filed a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) on behalf of the operator. When he arrived at the helicopter pad about 0700, the pilot was already there. The pilot, the crew boss, and the service truck driver held a brief meeting. The driver departed for the first field that would be sprayed that day. About 0745, the pilot did his preflight checks on the helicopter, warmed it up, and then departed for the field about 0800. At 0823, the pilot began spraying the field, completing the first job at 0857. After completing another field, the pilot arrived at the next site, and the service truck reloaded the helicopter. The job began at 0945, and ended at 0950. At the next field, the crew again loaded the helicopter was with spray and "topped off" the fuel tanks. The crew boss departed in his truck, traveling west, and the pilot departed the loading platform about 0955, traveling in a southwest direction toward the next field. Then, the crew boss witnessed the helicopter making a long, left turn. He lost sight of the helicopter as it flew over his truck. When he looked in his rearview mirror, he saw the helicopter impact the ground. According to a Federal Aviation Administration (FAA) inspector, two roads ran perpendicular to the accident site; Highway 190, which ran east and west, and Westwood Avenue, which ran north and south. The pilot departed from a service truck about one block north of Highway 190, west of Westwood Avenue, in a southwest direction. The destination field was 2 miles to the west, just south of Highway 190. As he crossed Highway 190, the pilot made a wide, left turn. Shortly thereafter, a witness, driving northbound on Westwood Avenue, saw the helicopter on his left-hand side, traveling parallel to him in a northbound direction. When the witness came to a stop sign (intersection of Highway 190 and Westwood Avenue), the helicopter maneuvered up and over power lines running east to west, south of Highway 190. The helicopter then turned left about 90 degrees (west), followed by another left turn of 90 degrees (south). The nose suddenly pitched down and the helicopter impacted the ground. The wreckage site was 1/2 block away from the intersection of Highway 190 and Westwood on the north side. PERSONNEL INFORMATION A review of FAA airman records revealed that the pilot held a commercial pilot certificate with airplane single-engine land and helicopter ratings. The pilot held a second-class medical certificate that was issued on October 12, 2002. It had the limitation that the pilot must have glasses available for near vision. An examination of the pilot's most recent medical application indicated an estimated total flight time of 10,650 hours. The Safety Board investigator-in-charge (IIC) interviewed the crew boss via telephone. When asked if the pilot's mental and physical condition seemed normal that day, the crew boss reported "yes and no." The pilot flew the helicopter back to the service truck every 5 minutes. The crew boss had a flag in the back of his pickup that indicated the wind direction. After spraying the first field, the pilot made his landing approach downwind, which was unusual. The crew boss did not question the pilot because "he may have had his own reasons for doing it." The crew boss indicated that the service truck driver also noted that the pilot was making downwind landings. The IIC interviewed the widow of the pilot. She reported that he was in good spirits the day prior to the accident, and she did not sense anything out of the ordinary. The day of the accident the pilot awoke about 0500 and departed for work. The pilot did not take any medications, but he did smoke cigarettes. The IIC interviewed a friend of the pilot, who was also a helicopter pilot. He had known the accident pilot for approximately 20 years. He described the accident pilot as an excellent, cautious pilot, and did not report any problems with Harvest Enterprises, or the accident helicopter. The last time he had seen the accident pilot was about 1 month prior to the accident. AIRCRAFT INFORMATION The airplane was a Bell 47-G4, serial number 7670. A review of the airplane's logbooks revealed a total airframe time of 10,110.2 hours at the last 100-hour annual inspection. An annual inspection was completed on May 8, 2002. At the 100-hour inspection dated February 15, 2003, the Hobbs meter read 558.7. At the accident scene the Hobbs meter read 623.2. The helicopter had a Textron Lycoming VO-540-B1B3 engine, serial number L-472-43. Total time on the engine at the last 100-hour annual inspection was 511.1 hours. A review of the helicopter's maintenance records revealed that an annual inspection was due by May 31, 2003. The inspection was not done. One of the main rotor blades (PN 47-110-250-21) had exceeded its hourly life by 18 hours. WRECKAGE AND IMPACT INFORMATION FAA inspectors examined the wreckage at the accident scene. The helicopter was consumed by a post impact fire and came to rest between a tree and a road, facing south. The main rotor blades remained attached to the helicopter. The fuel cap on the left tank was about 10 feet from the wreckage. Cut braches were on the ground around the helicopter. The skid guard was in the tree. All major control surfaces were accounted for at the accident site. Portions of the spray boom were about 50 feet in front of the main wreckage. MEDICAL AND PATHOLOGICAL INFORMATION The County of Tulare Coroner completed an autopsy. The autopsy concluded that the death was the result of injuries sustained in the accident. The FAA Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, conducted a toxicological examination on July 22, 2003. The report was negative for cyanide, volatiles (ethanols), and drugs. The test was positive for carbon monoxide at 11 percent. TESTS AND RESEARCH FAA inspectors completed an additional examination on the helicopter on June 18, 2003. They checked the control cables and linkages for continuity. There was no evidence of any preimpact discrepancies. Maintenance technicians removed the transmission from the engine to check for abnormal or excessive clutch wear. They detected no abnormal or excessive wear. The Textron Lycoming representative, a party to the investigation, examined the engine under the auspices of an FAA inspector on July 17, 2003. Post impact fire destroyed the fuel and ignition systems. The representative removed the valves from the cylinders and observed no indications of stuck valves. He checked the engine for foreign object ingestion; he found none. There were no signatures or conditions consistent with any premishap catastrophic engine failure. Fire damaged the magnetos, and they were not in a testable condition. The Lycoming representative visually examined the top spark plugs, and reported on their condition. All displayed undamaged electrodes. The electrodes from cylinders numbered 1, 3, and 5 were dark. The electrodes from cylinders numbered 2, 4, and 6 were normal. He did not examine the bottom spark plugs. ADDITIONAL INFORMATION The IIC interviewed the operator. He reported that the pilot fueled the helicopter from the upper deck of the service truck, and the service truck driver filled the chemical tanks from the bottom deck. The helicopter had been serviced with 15 gallons of fuel and 80 gallons of chemical. The pilot flew the helicopter with the right door removed and the left door on and closed.

Probable Cause and Findings

loss of control for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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