NTSB Factual Report

On May 22, 2001, a Piper PA-18-105 Special airplane, N7155K, departed the Sheffels Ranch private airstrip near Wilbur, Washington, on a 14 CFR 91 aerial observation flight. The reported purpose of the flight was to survey the farm's fields, with the pilot (one of the owners of the farm and the aircraft) and a farm worker aboard. The pilot and passenger were last seen about 2015. When the flight did not return as expected, the pilot's family initiated a search for the aircraft. The wreckage of N7155K was located about 0130 on May 23, 2001, about 3 miles northwest of Wilbur. The aircraft was substantially damaged, the private pilot was fatally injured, and the passenger was seriously injured. Visual meteorological conditions were reported at Ephrata, Washington, at 1950, and no flight plan had been filed for the flight. The surviving passenger reported that the flight was bound for the Wilbur, Washington, airport (2S8) at the time the accident occurred.

The passenger reported that the pilot fueled the aircraft before departure. He stated that he and the pilot took off and flew the fields northwest of the farm, flying over the fields starting in the north and progressively working their way south. The passenger stated that after they looked at all the fields, the pilot asked him if he had to go home, or if he could fly back to the Wilbur airport and help the pilot put the plane away. The passenger reported that he told the pilot that he would go with him. The passenger stated that they then turned toward the Wilbur airport, and that that was the last thing he remembered about the flight. The crash site was approximately midway between the Sheffels Ranch private airstrip (approximately 5 nautical miles north-northwest of the Wilbur airport) and the Wilbur airport. No other witnesses to the accident were identified.

The 1950 METAR weather observation at Ephrata, Washington, reported conditions there as winds from 180 degrees true at 5 knots, visibility 20 statute miles, few clouds at 25,000 feet, temperature 30 degrees C, dewpoint 3 degrees C, and altimeter setting 29.93 inches Hg. The 1952 automated METAR observation at Moses Lake, Washington, reported conditions at Moses Lake as wind from 230 degrees true at 4 knots, visibility 10 statute miles, clear skies, temperature 31 degrees C, dewpoint 7 degrees C, and altimeter setting 29.91 inches Hg. Conditions were the same at Moses Lake at 2052, with the exception of calm winds, temperature 29 degrees C, and dewpoint 6 degrees C. According to U.S. Naval Observatory astronomical data, sunset at the crash site on May 22 was at 2036, with the sun's azimuth at sunset approximately 303 degrees true.

An on-site examination by an FAA inspector from the Spokane, Washington, Flight Standards District Office (FSDO) revealed that the aircraft had crashed in open, rolling terrain. Ground scars were noted on a generally east-to-west track from the first (most easterly) ground scar to the aircraft wreckage. The right navigation light was found buried about 1 inch into the ground in the most easterly ground scar. A larger ground scar was noted 16 1/2 feet west of the most easterly scar (NOTE: The aircraft's wing span is about 35.3 feet.) The aircraft wreckage was just west of this larger ground scar. The aircraft had come to rest with its nose on a heading of 085 degrees, and with the aircraft propeller (still attached to the engine and at the front of the aircraft) about 5 feet west of the larger ground scar. All major aircraft components were with the aircraft wreckage. The right wing was folded aft, and the left wing was folded forward. The cabin exhibited severe impact damage. The aircraft's tail and empennage were largely intact. One propeller blade was bent aft about 30 degrees at midspan, and the other propeller blade was nearly straight. Flight control continuity was established to the ailerons, elevator, and rudder by the FAA inspector. Fuel was found in both fuel tanks. The aircraft's airspeed indicator was photographed at an indication of 55 MPH. No evidence of fire was noted in the wreckage.

The aircraft, originally equipped with a 100- to 108-HP Lycoming O-235 series engine (according to the FAA aircraft registry), had been modified by installation of a 150-HP Lycoming O-320-A2B engine. An examination of this engine was conducted by FAA and Textron Lycoming investigators at the facilities of Discount Aircraft Salvage, Deer Park, Washington, on June 5, 2001. Textron Lycoming's report of this examination stated: "We found no evidence of a pre-impact mechanical malfunction of the engine or on the engine related accessories." No aircraft or engine logs were provided to the NTSB; however, information provided to the FAA indicated that the aircraft's last annual inspection was accomplished on May 22, 2000.

An autopsy on the pilot was conducted by Pathology Associates Inc., P.S., Spokane, Washington, under the authority of the Lincoln County, Washington, Coroner, at the Forensic Institute at Holy Family Hospital in Spokane on May 24, 2001. The pathologist attributed the pilot's death to injuries "due to blunt impact to head", with additional injuries to the heart and aorta "due to blunt force" contributing to death. The autopsy report stated that there was "no significant underlying natural disease." Toxicology tests on the pilot were also conducted by the FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma. The CAMI toxicology tests screened for carbon monoxide, cyanide, ethanol, and various legal and illegal drugs and did not detect any of these substances.

The pilot's father contacted the NTSB investigator-in-charge (IIC) by telephone approximately September 2001 to state that he understood that certain individuals had reported seeing low-flying U.S. Air Force C-17 military transport aircraft in the vicinity during the time frame of the crash, and to request that the NTSB investigate the possibility that a wake turbulence encounter from an aircraft on a low-level Military Training Route (MTR) was involved with the accident. In response to this request, the IIC reviewed the Seattle Sectional Aeronautical Chart and the U.S. Department of Defense (DOD) Flight Information Publication (FLIP), Volume AP/1B, "Area Planning - Military Training Routes". FLIP AP/1B (pertinent extracts of which were provided to the IIC by the FAA Seattle Automated Flight Service Station [AFSS]) provides detailed route descriptions and planning procedures for use by military aircrews for flight on low-level MTRs in U.S. airspace. Review of the Seattle Sectional and FLIP AP/1B disclosed three MTRs where the crash site directly underlay the low-level route structure (exclusive of route entry and exit corridors): IR324, IR325, and IR341. Telephone inquiries to the owning/scheduling installations of these three routes (McChord Air Force Base, Washington, for IR324 and IR325, and Naval Air Station Whidbey Island, Washington, for IR341) disclosed that no aircraft were scheduled to fly IR324 or IR325 between 1710 on the accident date and 0200 the following morning, and that no aircraft were scheduled onto IR341 from 2000 to 2400 on the evening of the accident or "for a few hours either side of this window." It was further noted that both Sheffels Ranch Airstrip and the Wilbur airport were identified as avoidance areas in the AP/1B route descriptions of all three MTRs. During the September 2001 telephone conversation with the pilot's father, the IIC asked the pilot's father to contact the individuals who reported seeing low-flying military aircraft and request that they provide statements to the IIC regarding their sightings.

NTSB Probable Cause

A collision with terrain for undetermined reasons.