LAX99FA301

The airplane collided with high-tension electrical transmission wires suspended across a valley. According to witnesses, the airplane had departed a local airport the morning of the accident. When the pilot had not returned home by nightfall, a concerned family member contacted the local authorities to report him missing. About 30 minutes later, an ALNOT was issued and the wreckage was located the following morning. Portions of the left wing and a severed skyline wire were found under the high-tension electrical power transmission lines. Two sets of electrical skyline wires cross the valley in a northwest-southeast direction passing approximately 500 feet northeast of the main wreckage location. The two sets of wires are about 50 feet apart and towers supporting the wires are on the hilltops to the northwest and southeast; the open span across the valley was 5,190 feet. At the center of the valley the wires are approximately horizontal and are suspended approximately 175 feet above the valley floor. Inspection of the airplane revealed that the leading edge of the left wing had an impact mark with a rust-colored, braided appearance resembling the skyline wire, there was also a similar scrape on the lower spar cap of the left wing that had remained attached to the airplane. A circular gouge was observed on the leading edge of one of the propeller blades; the diameter of the gouge corresponded to the end of the severed wire. The airframe and powerplant were inspected on-scene with no discrepancies noted.

History of flight

On September 9, 1999, about 1050 hours Pacific daylight time, a Piper PA-22-150, N1775P, collided with steel wires strung between high tension towers and impacted terrain 5 miles northeast of Strathmore, California. The airplane, operated by the pilot/owner under the provisions of 14 CFR Part 91, was destroyed. The private pilot sustained fatal injuries. Visual meteorological conditions prevailed in the area throughout the day. No flight plan was filed for the personal flight that departed the Eckert Airport around 0900.

Eckert Airport, where the airplane is based, is a non-towered airport located in Strathmore. According to family members, the pilot had dropped off his daughter at school about 0830 and made plans to pick her back up at 1500 the same day. He had told his spouse that he was going to work on his airplane in the interim. At 1700, the spouse had to pickup their daughter at school because the pilot had not arrived to pick her up at the specified time. On the way home they drove by the airport to see if the pilot was there. She stated that his vehicle was at the airport, but the airplane was gone.

When the airplane did not return by evening, a concerned family member called the Tulare County Sheriff's Department about 1940 to report the pilot missing. They also told the Sheriff's deputy that he likes to fly around Success Valley area near Milo CDF. At 2230, the Federal Aviation Administration (FAA) was notified and an Alert Notice (ALNOT) was issued.

According to mission logs obtained from the United States Air Force Rescue Coordination Center (AFRCC), an emergency locator transmitter (ELT) beacon signal was identified via an orbiting satellite at 1221 on the day of the accident. After the first ELT signal at 1221, two passes by orbiting satellites reported negative contact. At 1500, a merge location of two ELT hits was identified. There was a negative pass made by satellite at 1501, and negative reports of an ELT signal from airborne aircraft. At 1516, another merge location was identified in the same area, and at 1522, AFRCC activated the mission with the California Civil Air Patrol (CAP) squadron. The CAP localized the ELT signal to a probable accident site location and then provided the coordinates to the local authorities, who located the airplane in Success Valley the following morning at 0800.

A Safety Board investigator found an outboard portion of the airplane's left wing under electrical power transmission wires; a severed skyline wire was also on the ground adjacent to the wing debris. A skyline wire is a nonconductive steel cable that passes in-between high-tension towers for structural purposes. Two sets of electrical skyline wires, operated by the Southern California Edison Company, cross the valley in a northwest-southeast direction passing approximately 500 feet northeast of the main wreckage location. The two sets of wires are approximately 50 feet apart and towers supporting the wires were visible on the hilltops to the northwest and southeast; the open span across the valley was 5,190 feet. At the center of the valley the wires are approximately horizontal and are suspended approximately 175 feet above the valley floor.

Personnel information

Personal flight logs were unavailable for review by a Safety Board investigator. Review of the FAA Airman Certification records revealed that the pilot received his private pilot certificate on June 23, 1982.

Review of the FAA Medical Certification records revealed that the pilot held a third-class medical, which was issued on February 9, 1999, with no limitations. At that time he reported that he had accrued 1,000 hours, with 40 hours in the past 6 months.

Aircraft information

Review of the airplane logbook and engine logbooks disclosed that on July 1, 1999, an annual inspection was completed. The airframe manufacturer's representative noted that the airplane was manufactured with a tricycle landing gear arrangement. Examination of the wreckage disclosed that the nose landing gear had been removed and the aircraft converted to a conventional landing gear configuration with the addition of a tail wheel assembly.

Meteorological information

The aviation surface weather report from the Porterville Municipal Airport, located approximately 12 miles southwest of the accident site, reported the weather at 0755 to be 8 miles visibility; winds from 160 degrees at 4 knots; temperature 66 degrees Fahrenheit; dew point of 43 degrees Fahrenheit; and altimeter setting 29.86 inHg. Weather reported at 1055 was 10 miles visibility; winds from 290 degrees at 5 knots; temperature 81 degrees Fahrenheit; dew point 48 degrees Fahrenheit; and altimeter setting 29.85 inHg.

Wreckage and impact information

The accident site was located near the center of a wide valley in rolling hilly terrain on the east side of the San Joaquin Valley at the foothills of the Sierra Nevada Mountains. Dry natural grasses covered the hills. The valley extended in a northeast-southwest direction and turned to the north approximately 2 miles northeast of the accident site. To the northwest and southeast of the site, mountains formed the valley and rise approximately 500 feet above the floor. The elevation of the accident site was about 700 feet msl. The entire airplane was located at the accident site and there was no fire.

The wires were identified as: the Big Creek 3 - Springfield (southwest set), and Big Creek 4 - Springfield (northeast set) circuits, and operate at 220 kilovolts. Each high voltage tower supports five wires, three copper electrical conductors and two steel, nonconducting, skyline wires. The three electrical conductors are suspended from a horizontal beam near the top of the tower, are laterally abeam of each other, and each are separated by about 20 feet. The skyline wires extend from the top of the towers about 15 feet above and laterally in between the electrical conductors. The towers supporting the northeast set of wires (Big Creek 4) are approximately 50 feet taller than the towers supporting the southwest set of wires (Big Creek 3), and the resulting cable sets are vertically separated a like amount.

At the accident site, the northeastern of the two skyline wires of the Big Creek 3 system was severed. The southwestern skyline wire of the same set was visibly shiny over about 5 feet of its span above the accident site. An Edison Company lineman reported that damage to a wire dampener on the tower indicated to him that the airplane also impacted the southwestern skyline wire. The severed skyline wire, approximately 1-inch diameter, consisted of seven strands of cable and exhibited a hook of approximately 1/4-inch radius at the very end. The ends of the severed individual wires were necked down and exhibited a shear lip around the circumference. The three electrical conductors of the Big Creek 3 set and all five wires of the Big Creek 4 system were visibly undamaged.

There was a wreckage debris field over approximately 600 feet, with the central axis oriented northeast to southwest between the fuselage and the location on the ground beneath a shiny section of skyline wire. There was a shallow area of freshly disturbed dirt about 4 feet wide and 6 feet long approximately 20 feet northeast of the fuselage.

Underneath the shiny section of skyline wire was a small circular debris field of approximately a 50-foot radius consisting of pieces of airplane fabric cover, Plexiglas of thickness resembling a landing light lens, and light metal structure resembling wing rib structure. These components were subsequently identified as belonging to the left wing assembly.

The fuselage wreckage, with the right wing and empennage attached, was located approximately 500 feet southwest of the shiny section of skyline wire. The fuselage was on a magnetic bearing of approximately 230 degrees. The le