On April 24, 2009, at an undetermined time, an experimental Valentin Taifun 17 E II motor-glider, N20822, collided with terrain under unknown circumstances near Mammoth Lakes, California. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certificated private pilot and one passenger were killed; the airplane sustained substantial damage to the wings, fuselage, and empennage from impact forces. The cross-country personal flight departed Tonopah, Nevada, about 1500 Pacific daylight time, with a planned destination of Modesto, California. Visual meteorological conditions prevailed at Mammoth Lakes, the nearest reporting station, and no flight plan had been filed.

The Federal Aviation Administration (FAA) issued an alert notice (ALNOT) after family members notified them of the overdue airplane. The Civil Air Patrol discovered the wreckage on May 1, 2009.


A review of Federal Aviation Administration (FAA) airman records revealed that the 67-year-old pilot held a private pilot certificate with ratings for airplane single-engine land, instrument airplane, and glider.

His third-class medical certificate, issued on May 27, 2008, had the limitation that the pilot must wear corrective lenses.

An examination of excerpts from the pilot's logbook indicated an estimated total flight time of 966 hours as of the last entry on April 16, 2009. He logged 19 hours in the last 90 days, and 8 hours in the last 30 days. He had an estimated 310 hours in gliders. He completed a biennial flight review on May 28, 2008.


The airplane was an experimental Valentin Taifun 17 E II, serial number 1116. A review of the airplane’s logbooks revealed that the airplane had a total airframe time of 235 hours at the last 100-hour inspection on March 26, 2008. The logbooks contained an entry for an annual inspection dated January 29, 2008.

The engine was a Limbach L2400, serial number 1078. Flight log excerpts indicated that on July 31, 2008, at a total engine time of 243.5 hours, the time since major overhaul was 8 hours. The last entry in the flight log indicated a total time of 313.5 hours on April 20, 2009.


Mammoth Lakes (KMMH) was 10 nautical miles (nm) at 140 degrees from the accident site. The elevation of the weather observation station was 7,135 feet mean sea level (msl).

An aviation routine weather report (METAR) for KMMH issued at 1510 PDT stated: winds calm; visibility 10 miles; skies 4,200 feet overcast; temperature 7/45 degrees Celsius/Fahrenheit; dew point -4/25 degrees Celsius/Fahrenheit; altimeter 29.89 inches of mercury.

The METAR for KMMH issued at 1610 PDT stated: winds 230 at 10 knots gusting to 24 knots; visibility 10 miles; skies 2,900 feet scattered, 4,100 feet overcast; temperature 7/45 degrees Celsius/Fahrenheit; dew point -5/23 degrees Celsius/Fahrenheit; altimeter 29.87 inches of mercury.

The METAR for KMMH issued at 1710 PDT stated: winds 290 at 15 knots gusting to 22 knots; visibility 10 miles; skies 3,300 feet broken, 4,000 feet broken, 4,800 feet overcast; temperature 3/37 degrees Celsius/Fahrenheit; dew point -3/27 degrees Celsius/Fahrenheit; altimeter 29.89 inches of mercury.

A weather station at June Lake, California, (elevation 7,960 feet) was 270 degrees at 7 nm from the accident site. At 1502, winds were from the north at 6 knots gusting to 14 knots. At 1611, winds were from the southeast at 4 knots gusting to 10. At 1711, winds were from the southeast at 6 knots gusting to 12 knots.

A weather station at Crestview, California, (elevation 7,596 feet) was 210 degrees at 4 nm from the accident site. At 1512, winds were from the northeast at 5 knots gusting to 18. At 1623 and 1713, winds were from the northeast at 5 knots gusting to 17.


FAA on Scene Exam

An FAA inspector examined the airplane at the accident scene, and provided the following information.

The fuselage was in a small open area with the nose pointed approximately 090 degrees. The GPS position was 37 degrees 46.769 minutes north, 118 degrees 57.366 minutes west, at an elevation of about 8,000 feet msl.

The debris path was along 315 degrees, and headed up a shallow canyon. The bottom of the canyon opened up to the Owens River. Looking at the topography map, it appeared that this valley was open country that was fairly large and flat. The top of the canyon opened up into a large, flat wooded area, with a large sand flat located about 2 miles northwest of the top.

From the first impact with tree tops to the final resting position, the airplane traveled approximately 325 feet. As the airplane traveled through the trees (50-75 foot pine trees), both wings were torn off the fuselage, with the right wing about 35 feet from the fuselage. The right wing aileron and flap were about 25 feet from their respective wing with the right wing tip up in a tree. The right wing received a large amount of damage from striking a tree at the leading edge.

The left wing was about 30 feet from the fuselage. The left wing’s aileron and flap were in close proximity to the associated wing. The left wing was also damaged at the leading edge from striking a tree.

One of the propeller blade tips was found in the vicinity of the left wing.

The other propeller blade tip was located about 120 feet up the canyon beyond the fuselage. Both propeller blades were wood, and fragmented with only small pieces located.

The inspector verified rudder continuity.

Fore/aft movement of the control stick was limited, and required a moderate amount of force to move. Due to the impact, the forward portion of the control rod moved, but was broken just aft of the cockpit at a threaded fitting. The aft portion appeared to be intact, and movement of the elevator could be verified by moving this portion of the control rod.

The area just aft of the cockpit appeared to be crushed from the impact, and the aileron mixer assembly was also damaged. Left/right movement of the control stick was limited and difficult, but the mixer assembly could be actuated to the wing attach point on the right side.

The inspector could not positively identify or move the spoiler actuation system in the fuselage. Both spoilers were intact and retracted in the wings. They could be actuated where the control input was located at the wing roots.

Both left and right ailerons and flaps separated from their respective wings. The control rods appeared to be intact in the wings, and attached to the bell cranks.

The ignition key was in the on position. The master switch was on. All other switches were in the off position with the exception of the beacon switch. The throttle was full in, along with the fuel valve and choke.


The Mono County Coroner completed an autopsy, and determined that the cause of death was multiple traumatic injuries. The FAA Forensic Toxicology Research Team, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot.

Analysis of the specimens contained no findings for carbon monoxide, cyanide, volatiles, and tested drugs.


Engine Exam

Examination of the engine revealed no anomalies that would have precluded normal operation.

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