NTSB Factual Report

HISTORY OF FLIGHT

On July 2, 2008, about 1307 Pacific daylight time, an amateur built Mauck RV-6A, experimental airplane, N27WR, was substantially damaged when it impacted trees while maneuvering near Sierraville, California. The airplane was registered to Tahoe Athletic Adventures Inc, of Tahoe City, California, and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. The pilot, sole occupant of the airplane, was killed. Visual meteorological conditions prevailed at the time of departure, and no flight plan was filed for the personal local flight that originated from the Truckee-Tahoe Airport, Truckee, California, about 1254.

The afternoon of July 2, 2008, a concerned family member reported to the Federal Aviation Administration (FAA) that the airplane and pilot had not been seen since the flight departed the airport earlier in the day. The FAA subsequently issued an Alert Notification (ALNOT) and a search for the airplane was initiated. The airplane was located by air units on July 5, 2008, approximately 1050, in a heavily wooded area about 1.5 miles northwest of the Sierraville Deerwater Airport (O79), Sierraville.

Two witnesses located along the estimated flight path of the accident airplane reported observing an airplane similar to the accident airplane flying overhead at a low altitude. One witness, located about 18 miles southeast of the accident site stated that he had to momentarily pause his telephone conversation until the airplane passed overhead in a northerly direction. Another witness, located about 13 miles southeast of the accident site reported that she observed an airplane flying on an easterly heading and turning to a southerly course until she lost sight of the airplane. The witness stated that she didn't hear anything except a "swooshing" sound, which initially caught her attention.

There are no known witnesses to the accident sequence.

An image captured by the closed circuit surveillance video system at TRK revealed that the airplane was taxiing towards the runway at 1253.

PERSONNEL INFORMATION

The pilot held a private pilot certificate with airplane single-engine land and glider aero tow ratings. A second-class airman medical certificate was issued to the pilot on September 25, 2007, with the limitation stated "night flying prohibited." Review of the pilot's logbook records revealed that he had accumulated 167.8 hours total flight time, of which 68.8 hours were in the accident make/model. The pilot had recorded 24.7 hours of flight time in the previous 90 days and 7.2 hours in the 30 days prior to the accident. He completed a biennial flight review on September 20, 2007.

AIRCRAFT INFORMATION

The two-seat, low-wing, fixed-gear airplane, serial number (S/N) 21073, was manufactured in 1991. It was powered by a Lycoming O-360-A1A engine, serial number L-13080-36A, rated at 180 horse power and equipped with a Sensenitch two bladed fixed-pitch propeller. Review of aircraft maintenance logbook records revealed that a conditional inspection was completed on July 2, 2008, at a recorded tachometer reading of 203.2 hours. During the conditional inspection, the engine driven fuel pump was replaced. The tachometer reading at the accident site was 203.8 hours, .6 hours since the conditional inspection.

A fuel slip located within the wreckage indicated that on July 2, 2008, at 1240 PDT the pilot purchased 20 gallons of fuel.

METEOROLOGICAL INFORMATION

The automated weather observation system at the Truckee-Tahoe Airport (TRK), Truckee ,California, located about 24 miles southeast from the accident site, reported at 1245, wind from 210 degrees at 10 knots, visibility 10 statute miles, clear sky, temperature 28 degrees Celsius, dew point -02 degrees Celsius, and an altimeter setting of 30.15 inches of Mercury.

The automated surface observation system at the Blue Canyon Airport (BLU), Emigrant Gap, California, located about 32 miles southwest from the accident site, reported at 1252, wind from 240 degrees at 5 knots, visibility 2 statute miles, haze, clear sky, temperature 23 degrees Celsius, dew point 7 degrees Celsius, and an altimeter setting of 30.16 inches of Mercury.

Personnel from the United States Forest Service located at a lookout tower about 12 miles east southeast of the accident site stated that around mid day, visibility was about 1/4 to 1/2 miles with heavy smoke in the area.

A local law enforcement officer reported that the day of the accident, visibility was marginal due to smoke in the area of the accident.

WRECKAGE AND IMPACT INFORMATION

Examination of the airplane by a Federal Aviation Administration (FAA) inspector, who responded to the accident site revealed that the airplane came to rest inverted within a group of tall trees about 1.5 miles northwest of the Sierraville / Dearwater Airport (O79), Sierraville. The left wing was mostly separated from the fuselage and the engine was separated from the firewall. All primary flight controls were located at the accident site. The wreckage energy path measured about 200 feet from the initial point of contact to where the engine came to rest.

MEDICAL AND PATHOLOGICAL INFORMATION

The Sierra County Coroners office conducted an autopsy on the pilot on July 08, 2008. The medical examiner determined that the cause of death was "…blunt force 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. The report stated that positive results for 74 (mg/dl, mg/hg) of Ethanol was detected in the liver, 117 (mg/dl, mg/hg) of Ethanol was detected in the muscle, 20 (mg/dl, mg/hg) of Ethanol was detected in the blood, 26 (mg/dl, mg/hg) of Ethanol was detected in the spleen, 33 (mg/dl, mg/hg) of Ethanol was detected in the kidney, 20 (mg/dl, mg/hg) of N-Butanol was detected in the muscle, 3 (mg/dl, mg/hg) of N-Propanol was detected in the muscle, 1 (mg/dl, mg/hg) of N-Propanol was detected in the blood, and 1 (mg/dl, mg/hg) of N-Propanol was detected in the kidney. An unspecified amount of Diphenhydramine was detected in the liver.

It was noted by the toxicology laboratory that specimens exhibited evidence of putrefaction. The pathologist noted in the autopsy report that the "Postmortem blood ethanol concentration (64mg/dL or 0.064%) may be a decomposition artifact."

TESTS AND RESEARCH

On July 22, 2008, at the facilities of Plain Parts, Pleasant Grove, California, the recovered airframe and engine were examined by a representative from Textron Lycoming Engines under the supervision of the NTSB investigator-in-charge.

Examination of the airframe revealed that the fuselage forward of the rear part of the cabin was severely fragmented. The main wing spar was separated from the fuselage structure. Flight control continuity was established from the cockpit to all of the primary flight controls. The aileron and elevator control torque tubes were separated in multiple areas. The rudder control cables remained attached to the forward and aft sets of rudder pedals and were separated in multiple areas. All of the areas of separation were consistent with overload.

The attitude indicator was separated from the instrument panel and was disassembled and examined. The gyro was found intact and exhibited rotational scoring on the gyro housing.

The engine was partially attached to the engine mounts. The engine mount was separated from the engine firewall, however, various wires remained attached to both the firewall and mount structure. The forward portion of the crankcase was heavily damaged. The bottom left portion of the crankcase was missing. Cracks were observed on the top forward portion of the crankcase.

The propeller flange was separated from the crankshaft. The carburetor, alternator, starter, and oil cooler were separated from the engine. The top spark plugs, all engine accessories, valve rocker box covers were removed. The engine crankshaft would not rotate using a hand tool at the vacuum pump accessory mount pad. The number three and four cylinders were removed from the engine and exhibited normal operations signatures. Mechanical continuity was established throughout the engine and valve train.

The propeller remained attached to the propeller mounting flange, however was separated from the crankshaft. One propeller blade exhibited a substantial leading edge gouge about three to four inches in length. The propeller blade also exhibited span wise scratching on the forward side of the propeller blade. The other propeller blade was missing about four inches of the blade tip and exhibited chordwise scratching on the forward side of the blade.

No mechanical anomalies were noted with the recovered engine or airframe and flight control system.

NTSB Probable Cause

The pilot's failure to maintain clearance with trees and terrain while maneuvering Contributing to the accident was the reduced visibility in the area due to smoke.