NTSB Factual Report

HISTORY OF FLIGHT

On May 18, 2013, about 1838 Pacific daylight time, a Cessna 170B airplane, N2865C, was substantially damaged when it impacted terrain while on final approach to landing at the Auburn Municipal Airport (AUN), Auburn, California. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot and his passenger were fatally injured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The cross-country flight originated from the Crazy Creek Gliderport, near Middletown, California, about 1754 with an intended destination of AUN.

Information provided by the Federal Aviation Administration (FAA) revealed that the friend of the pilot contacted the FAA on the evening of May 18, 2013, after he became concerned when the pilot had not arrived at his intended destination. The FAA subsequently issued an Alert Notification (ALNOT). The United States Air Force Rescue Coordination Center (ARCC) and local law enforcement commenced search and rescue operations throughout the area. The wreckage was located by aerial units on the morning of May 19, 2013.

A friend of the pilot reported that he departed Crazy Creek Gliderport prior to the departure of N2865C. As he was over Lincoln, California, he was contacted via radio by the pilot of N2865C, who informed him that he was about 18 minutes behind. The witness stated that while he was on the ground at Auburn, and after he refueled his airplane, he briefly saw the accident airplane on downwind, however, didn't pay much attention to it as he was trying to put his airplane in the hangar. A few minutes later, he went to pick the accident pilot and passenger up, however, could not find them. He suspected the airplane that he saw wasn't them, however, about an hour later he grew concerned and notified authorities.

There were no reported witnesses to the accident sequence.

PERSONNEL INFORMATION

The pilot, age 59, held a private pilot certificate with an airplane single-engine land rating, which was issued on January 28, 2009, and a glider rating which was issued on April 4, 1992. A third-class airman medical certificate was issued to the pilot on March 26, 2012, with the limitation that stated "must have glasses for near vision."

Review of the pilot's logbook revealed that as of the last recorded entry, dated May 2, 2013, he had accumulated 476.2 total flight hours in single-engine land airplanes, of which 432.1 hours was in the accident make/model airplane, 0.5 hours were in the previous 30 days, 2.75 hours in the previous 60 days, and 3.75 hours were in the previous 90 days. The pilot's most recent flight review was completed on January 22, 2013. Review of the pilot's logbook for gliders revealed that as of the most recent entry, dated May 18, 2013, he had accumulated 93.7 hours in gliders.

AIRCRAFT INFORMATION

The four-seat, high-wing, fixed-gear tailwheel equipped airplane, serial number (S/N) 26408, was manufactured in 1954. It was powered by a Continental Motors O-300-A engine, serial number 31117-D-3-A, rated at 145 horse power, driving a McCauley 1C172 fixed pitch propeller. The airplane is equipped with wing flaps which can be positioned in 0, 20, 30, or 40-degree positions by the flap handle, located between the two front seats.

The Cessna 170B operators manual states in part on page 28, item 3, "…the flaps on the 170 allow steep, well controlled approaches making slips unnecessary. Slips with full flaps are to be avoided because if the slip is extreme enough at a relatively high airspeed, the airflow is disturbed over the tail surface resulting in a sudden and steep downward pitch of the nose."

Review of the airframe and engine maintenance logbooks revealed that the most recent annual inspection was completed on December 21, 2012, at an airframe total time and tachometer hour reading of 3,688.5 hours, and engine total time since major overhaul of 395.5 hours.

METEOROLOGICAL INFORMATION

A review of recorded data from the Auburn Municipal Airport (AUN) automated weather observation station, located about 0.24 miles west of the accident site, revealed at 1835 conditions were wind from 300 at 4 knots, visibility 10 statute miles, clear sky, temperature 24 degrees Celsius, dew point 5 degrees Celsius, and an altimeter setting of 30.07 inches of mercury. Using the reported weather conditions and field elevation, the calculated density altitude was about 2,830 feet. Using the reported wind heading and velocity, the airplane would have had an approximate 3 knot headwind component.

Review of the United States Naval Observatory's database, the sun began transit at 1301. Official sunset was 2013 with the end of civil twilight at 2043.

AIRPORT INFORMATION

The Auburn Municipal Airport is a non-towered airport that operates in class E airspace. The airport features a single asphalt runway, 3,700-feet long and 75-feet wide, oriented on 070 and 250 degrees respectfully. The reported airport elevation is 1,539 feet. Runway 25 features a 1.5 percent downhill gradient. The two-light precision approach path indicator (PAPI) system was out of service at the time of the accident, and a Notice to Airman (NOTAM) was active at the time of the accident. Rising terrain was observed northeast and southeast of the runway approach path.

WRECKAGE AND IMPACT INFORMATION

Examination of the accident site revealed that the airplane impacted wooded terrain about 1,257 feet east of the runway 25 threshold. The wreckage came to rest inverted oriented on a magnetic heading of about 040 degrees. All major structural components of the airplane were located within about 30 feet of the main wreckage. One tree located immediately west of the main wreckage had the right wing lodged between branches. No other trees or vegetation surrounding the accident site and wreckage were damaged.

The fuselage was mostly intact. The engine was crushed aft into the firewall and instrument panel. The cabin structure was compressed downward. The lower part of the fuselage surrounding the gearbox was torn open. The fuselage from the aft seats to the empennage was intact and bent/buckled throughout. The structure underneath the rear seats was partially torn open on the bottom side of the fuselage and buckled.

Both front seats were equipped with dual shoulder strap inertial reel shoulder harnesses. Seat belts were cut by first responders. The right seat was found removed from the wreckage. The left seat was partially attached to its seat rails. Secondary seat stops were present on the seat rails for both front seats. The rear, inboard seat foot of seat 1 was against the secondary seat stop.

The right wing was separated from the fuselage and lodged within a tree about 15 feet above the ground. The wing exhibited a circular impression at the flap/aileron junction that extended from the leading edge aft to the main spar. The right flap was separated from the wing and located adjacent to the fuselage. The right aileron remained attached via all of its mounts. The wing structure and fuel tank was displaced from the remainder of the wing and located on the ground below the tree. The left wing was partially attached to the fuselage and located slightly underneath the fuselage. The wing exhibited leading edge crushing throughout its span. The outboard portion of the wing exhibited approximate 30-degree crushing from the landing light outboard to the wingtip. The left aileron remained attached via all of its mounts. The left flap remained attached to the wing via all of its mounts. The stall switch from the left wing was intact and displaced from the wing with impact damage noted. The switch functioned mechanically, however, would not function electrically.

The horizontal stabilizer, elevators, vertical stabilizer, and rudder remained attached to the empennage. The right elevator and horizontal stabilizer were bent on the outboard tip. The left elevator and horizontal stabilizer were bent and crushed on the outboard tip.

Flight control cable continuity was confirmed from each cockpit control to the associated flight control through either tension overload separations or cable cuts made during recovery of the wreckage. The elevator push/pull tube was fractured during the impact. The flap handle was displaced from its structure but appeared to be in the fully extended position. Damage to the flap tracks was indicative of the flap rollers being in the fully extended position.

Examination of both the left and right wings revealed no evidence of a birdstrike or collision with objects. In addition, no evidence of a bird strike was observed inside the cabin area.

The engine remained partially attached to the fuselage by various hoses and cables. The left magneto, starter, and the carburetor were separated from their respective mounts. The number six cylinder was partially pulled away from the crankcase and exhibited impact damage to the forward part of the barrel. The remaining cylinders remained secure. The internal areas of the cylinders including the intake and exhaust valves were examined using a lighted borescope. All cylinders exhibited unremarkable signatures with the exception of a blue colored stain on the number three, four, and six intake valve faces. The crankshaft behind the flange was mostly separated and exhibited a dull separation surface with 45-degree sheer lips consistent with overload and impact damage.

The crankshaft was rotated by hand using a hand tool attached to the propeller flange. Rotational continuity was established throughout the engine and valve train. Thumb compression and suction was obtained on all six cylinders.

The left magneto was impact damaged and rotated by hand. No spark was observed, however, two of the posts were separated from the magneto. The magneto was disassembled and all internal parts were intact except for the large gear which was damaged. The damage was consistent with impact damage to the magneto. The right magneto drive shaft rotated by hand freely and produced blue spark across all six posts with impulse coupling engagement.

The propeller remained attached to the crankshaft propeller flange. One propeller blade was mostly straight and exhibited chordwise scratches on the forward portion of the blade. The opposing blade was bent aft beyond 90 degrees about mid span and slightly twisted near the blade tip.

No evidence of any preexisting mechanical anomalies that would have prevented normal operation of the airframe and engine were found during examination of the engine and airframe.

MEDICAL AND PATHOLOGICAL INFORMATION

The Placer County Coroner conducted an autopsy on the pilot on May 20, 2013. 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 toxicology tests was positive for 68 (ug/ml, ug/g) Acetaminophen in Urine.

Information provided from CAMI revealed that Acetaminophen is a common over the counter analgesic/antipyretic (Tylenol). It is available in many oral dosage forms and in combination with various decongestants and/or antihistamines. It is also available by prescription in combination with various opiate derivatives

TESTS AND RESEARCH

A Garmin GPSmap 296 hand-held GPS was located within the main wreckage and was sent to the National Transportation Safety Board Vehicle Recorders Laboratory, Washington, D.C. for further examination.

The Garmin GPSMap 296 was found to have sustained impact damage to the extern case and LCD screen. Stored data was recovered from the GPS utilizing a flash memory chip reader.

The data for the accident flight showed that following the airplane's departure from Middletown, it continued on an easterly heading towards Auburn. The track indicated the flight entered the airport traffic pattern on the downwind leg at an altitude of about 2,568 feet, then continued a descent through base and final approach. The last three recorded GPS points depicted a course of 295, 281, and 267 degrees, groundspeeds of 65, 63, and 64 knots, at altitudes of 1,948, 1,867, and 1,744 feet mean sea level (msl) receptively. The last recorded GPS point was located about 130 feet east of the accident site.

A performance study was completed using the downloaded GPS data. The airplane's flight path distance was plotted versus altitude and compared to 3-degree glide slope to the threshold of runway 25 and the PAPI. The data showed that the accident aircraft was well above the 3-degree glide slope to both the PAPI and runway threshold. During the final minute of flight, the airplane descended more than 500 feet during a 180-degree turn from downwind to final for runway 25. The aircraft's descent rate was increasing throughout the turn onto final from -250 feet/min initially, to more than -800 feet/min as it completed the turn. In addition, about halfway through the turn from downwind to final, the downward flight path angle increased to about 9 degrees. For more information see the Performance Study within the public docket for this accident.

NTSB Probable Cause

The pilot's failure to maintain airplane control during approach to landing, which resulted in an inadvertent stall and subsequent spin.