SEA07FA106

During a VFR cross country flight over mountainous terrain, the airplane encountered deteriorating weather conditions. Weather satellite images show clouds in the vicinity of the accident site, with mountain waves just south of it. The surface chart indicated that a cold front was moving through the area. A resident in the vicinity of the accident site reported that on the morning of the accident, the weather was bad and he was unable to see the top of the mountain. Radar data indicated that the airplane was flying a constant altitude and course during its last three minutes of recorded flight. The last radar return was about one nautical mile short of the impact site, which was located on rugged mountainous and heavily forested terrain. There were no witnesses to the accident. No evidence of a mechanical failure or malfunction was noted during the post accident inspections.

History of flight

On April 18, 2007, at 0728 Pacific daylight time, a Piper PA-28-140, N8168N, was substantially damaged when it impacted terrain near Tehachapi, California. The airline transport pilot and his passenger were killed. Memley Aviation Inc. of Fresno, California, was operating the aircraft under 14 Code of Federal Regulations Part 91. A flight plan had not been filed for the personal, cross-country flight, which had originated from Fresno, California, about 0630. The intended destination was Lancaster, California. Visual meteorological conditions prevailed for the departure from Fresno. Residents in the vicinity of the accident site reported instrument meteorological conditions prevailed on the morning of the accident.

The pilot's wife said that the airplane departed about 0630. Federal Aviation Administration (FAA) radar first detected the airplane at 0638:51, at 3,300 feet mean sea level (msl), immediately south of Fresno, California. The last radar return was at 0727:42, about 1 nautical mile (nm) short of the impact site. The airplane was at 6,900 feet msl, traveling at a ground speed of 130 knots, and on a heading of 140 degrees magnetic.

The United States Air Force Rescue Coordination Center (AFRCC), located at Tyndall Air Force Base, Florida, received a satellite relayed Emergency Locator Transmitter signal, in the Tehachapi area, at 0836. Concerned family members of the pilot and passenger called authorities at approximately 1300. Search and rescue members spotted the downed aircraft on April 19, 2007 at approximately 0700. There were no witnesses to the accident.

Personal information

The 73 year old pilot's most recent second class Federal Aviation Administration (FAA) medical certificate was issued on March 23, 2006. On that application he stated that he had 10,000 hours of flight experience. His last flight review was satisfactorily completed on January 22, 2007.

The 16 year old passenger was a student pilot who had soloed on January 9, 2007.

Aircraft information

The airplane was a single engine, propeller-driven, fixed landing gear, four seat airplane, which was manufactured by Piper Aircraft, Inc., in 1968. The airplane had a maximum takeoff gross weight of 2,150 pounds. It was powered by a Lycoming O-320-D2A, four cylinder, reciprocating, air cooled, carbureted engine, which had a maximum takeoff rating of 160 horsepower at sea level. Maintenance records indicate that the last 100-hour inspection was performed on March 21, 2007; the airframe had 12,981 hours of flight on it at the time of the accident.

The airplane's navigation equipment included a Garmin GNS 430 GPS/Nav/Comm. The Garmin GNS 430 GPS system was approved for instrument flight rules (IFR) flight on May 29, 2006.

Meteorological information

At 0752, the weather conditions at Meadows Field Airport (elevation 507 feet), Bakersfield, California, located 295 degrees for 36 nm from the accident site, were as follows: wind 310 degrees at 6 knots; visibility 10 statue miles; clear of clouds; temperature 45 degrees Fahrenheit; dew point 34 degrees Fahrenheit; altimeter setting 30.21 inches of mercury.

At 0752, the weather conditions at the United States Weather Bureau Station (elevation 4,512 feet), Sandberg, California, located 200 degrees for 22 nm from the accident site, were as follows: wind 350 degrees at 18 knots gusting to 32 knots; visibility 10 statue miles; cloud condition overcast at 700 feet; temperature 29 degrees Fahrenheit; dew point 25 degrees Fahrenheit; altimeter setting 30.03 inches of mercury.

At 0500, a radiosonde was launched from Vandenberg Air Force Base, California, located 240 degrees for 105 nm from the accident site with the following results: wind at 7,000 feet, 283 degrees at 29 knots.

Weather satellite images taken at 0800 show clouds in the vicinity of the accident with mountain waves just south of the accident site. The satellite data, upper air charts, and pilot reports (PIREPs) indicate that the cloud tops in the area of the accident were probably about 7,500 feet to 8,000 feet mean sea level.

The 0800 surface chart indicates that a cold front was moving through the area.

A resident of the Alpine Forest community (approximately 1.5 nm northeast of the accident site) said that on the morning of the accident, the weather was bad and he was unable to see the top of the mountain. When the National Transportation Safety Board lead investigator arrived on scene on April 20, 2007, he found approximately 2 inches of snow on the wreckage.

Wreckage and impact information

The airplane impacted terrain near the community of Alpine Forest (elevation 6,925 feet), Tehachapi, California. It was situated on a very steep, heavily forested slope. The wreckage debris path was about 30 feet in length on a 140 degree magnetic heading. All of the airplane's major components were accounted for at the accident site.

The main fuselage and cockpit area were totally compromised, and the empennage was crushed upwards and accordioned into the fuselage. The engine and forward cockpit section had separated from the fuselage and were found approximately 15 feet up hill from the main wreckage. The right wing remained attached to the center section of the fuselage and its tip was found about 30 feet down hill. The left wing had separated from the fuselage at its root and was found under the empennage. The outboard one third of the left wing had separated and was found approximately 75 feet up hill.

The throttle quadrant was located and the throttle was found in the full forward position. The altimeter's Kollsman window was set at 30.20 inches of mercury. The two VOR navigation control heads had their Omni Bearing Selectors (OBS) set for 124 degrees and 127 degrees respectively.

After the wreckage was recovered, on May 10, 2007, a team of investigators examined the engine. Mechanical continuity was established throughout the rotating group, valve train and accessory section during hand rotation of the crankshaft. Compression was produced in all four cylinders. A visual examination of the combustion chambers of the cylinders was made and all appeared in good mechanical condition. The spark plugs coloration was consistent with normal operation, according to the Champion Spark Plugs Check-A-Plug chart AV-27. The propeller assembly had separated from the crankshaft flange. Both propeller blades displayed leading edge gouging, torsional twisting, chordwise striations across the cambered surfaces and "S" bending.

Physical evidence observed at the accident site indicated the airplane was in level flight at impact. No evidence was found of any pre-impact mechanical discrepancies with the airplane's airframe or engine that would have prevented normal operation.

Medical and pathological information

The Kern County Sheriff's Department Coroner Division, Bakersfield, California, performed an autopsy on the pilot on April 20, 2007. They determined that the cause of death was "multiple blunt trauma."

The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report, carbon monoxide, cyanide, volatiles, and drugs were tested, and the results were negative.

Test and research

A National Transportation Safety Board aeronautical engineer analyzed the radar and weather data, and determined that the airplane's ground speed at the time of the accident was 130 knots. He determined that the airplane had a tail wind of 20 knots; therefore its true airspeed was 110 knots.

The airplane was flying in a geographical area, which is found, on the FAA's Los Angeles Sectional Aeronautical Chart. This chart is divided by ticked lines of latitude and longitude, which form a grid network. Each quadrangle has a maximum elevation figure (MEF), which is enunciated in large bold figures. This figure is the highest known featu