WPR11FA155

The airplane’s encounter with severe turbulence, which resulted in the in-flight breakup of the airplane. Contributing to the accident was the pilot’s inadequate preflight planning.

The pilot had no previous experience flying the experimental airplane, although he did have the last registered owner give him a 1-hour overview of the airplane, including a demonstration of the flight controls. The pilot appeared to be rushed and departed in the airplane without performing a test flight. There was no record of the pilot receiving a weather briefing. The previous registered owner said that the airplane did not perform well in windy conditions due to its weight and design. The airplane departed and proceeded south while gradually ascending and leveling off about 9,500 feet mean sea level (msl). About 30 minutes after departure, the airplane turned to an easterly direction and began a 12-minute ascent to 14,800 feet msl. The airplane proceeded in a meandering southeasterly course and descended to 12,000 feet msl. About 30 minutes later, the airplane turned to a meandering easterly course and started another gradual descent to 7,000 feet msl. During the last 12 minutes of the flight, the altitude fluctuated between 5,800 and 7,300 feet msl. The final radar return was located 1 mile west of the accident location and showed the airplane 1.5 hours after departure, at 7,100 feet msl (5,170 feet above ground level). In the vicinity of the accident site, around the time of the accident, there was a westerly surface wind at 40 mph, gusting to 56 mph. The highest surface wind was reported north of the accident location with wind gusts up to 73 mph. At 9,500 feet msl, the wind was from 245 degrees at 28 knots, which resulted in a strong local vertical wind shear capable of producing moderate or greater turbulence in the layer. Several pilots operating in the area of the accident site reported encountering updrafts and downdrafts, from 1,500 to 2,500 feet per minute, and unusually strong low-level wind and turbulence. The airplane debris field was comprised of large heavy debris (engine and landing gear) near the location of the initial impact and lighter debris that was distributed downwind. Two items, a 2-foot-long section of vertical stabilizer and an 8-inch piece of rudder skin, were found 1,820 feet and 2,880 feet (respectively) downwind from the main debris scatter area, significantly farther from the main debris scatter area, which would indicate these two items were the first to depart the airplane. The overall debris pattern, and lack of damage to the wings is consistent with an in-flight breakup of the airplane. The rapid descent was probably initiated by the separation of about half of the vertical stabilizer as a result of severe turbulence while the airplane was near the location of the final radar return. The departure of a portion of the vertical stabilizer and pieces of the rudder would have resulted in the pilot’s inability to control the airplane, followed by a rapid descent and subsequent in-flight breakup.

HISTORY OF FLIGHT On March 7, 2011, about 1500 Pacific standard time, a Muse KR2, N122B, impacted terrain 14 miles east of Newberry Springs, California. The pilot was killed and the airplane was substantially damaged. The experimental category airplane was registered to a private individual, and operated by the commercial pilot under the provisions of Title 14 Code of Federal Regulations, Part 91 as a personal cross-country flight. Visual meteorological conditions prevailed for the flight, and a visual flight plan had not been filed. The flight originated from Porterville, California, at 1330. The pilot bought the airplane from the registered owner on Monday, March 7. A handwritten bill of sale was located within debris field. The registered owner stated that the pilot had no previous experience flying KR-2 airplanes, and he spent approximately 1 hour giving the pilot an overview of the airplane and showing him the controls. The pilot stated his intention was to fly 96 miles to Fox Field, which is located in the Lancaster, California, area. The pilot seemed to be in a hurry and departed the airport in the airplane without test flying it. The takeoff appeared normal to the registered owner. The airplane’s empty weight is 629 lbs, has an 80-hp engine that burns about 5 gallons per hour, and was loaded with 17 gallons of fuel. The registered owner stated that the airplane did not perform well in windy conditions due to its weight and design. Although the airplane was not actively tracked or monitored by any air traffic control personnel, it was captured by Federal Aviation Administration (FAA) ground tracking radar, and the National Track Analysis Program (NTAP) radar data files enabled reconstruction of the airplane's flight path. The data files were combined, processed, and plotted using DeLorme XMap 7. The pilot departed the Porterville Airport at 1330 on March 7, proceeded south to the town of Gorman, and then east towards the town of Needles. The first radar return in the data file occurs at 1358:28, 5,900 feet mean sea level (msl), in the vicinity of Meridian, California, 20 miles south of Bakersfield. The track proceeds south and increases altitude steadily to about 9,500 feet. At 1404, when over Gorman, the track turns to an easterly direction, and the altitude starts a steadily increase. By 1417, the airplane is at 14,800 feet msl near Edwards AFB. The track turns, meandering in a southeasterly direction, and the altitude decreases to 12,000 feet msl. At 1431, the track turns left onto a meandering easterly course and starts a gradual descent towards 7,000 feet msl. The last 12 minutes of data show the track altitude fluctuating between 5,800 and 7,300 feet msl. The final radar return was recorded at 1500:23, at 7,100 feet msl (5,170 feet above ground level (agl)), 1 mile west of the accident location. An alert notice (ALNOT) was released by the FAA on the evening of March 8, and the wreckage was located by the San Bernardino County Sheriff's Air Support unit in the early morning of March 9. The energy path of the wreckage starting at the initial impact point was along a 052-degree (magnetic) bearing line, and extended for a distance of 185 feet. The majority of the debris was scattered easterly along this line of bearing. The most distant piece of debris was a piece of rudder skin located 2,665 feet east of the main wreckage. The majority of the wreckage was located within 500 feet of the initial impact. AIRCRAFT INFORMATION The two seat, low wing, fixed gear, experimental category airplane, serial number 7774, was manufactured in 1993. It was powered by a Revmaster R-2100D, serial number 2395, 4-cylinder, 80-hp engine, and was equipped with a Sterba Experimental 52-50 fixed pitch wood propeller. Review of the airplane's maintenance logbooks showed an annual inspection completed on August 12, 2010, at a total aircraft time of 333.2 hours. PERSONNEL INFORMATION The pilot, age 68, held a commercial pilot certificate with ratings for airplane single-engine land, airplane multi-engine land, and instrument airplane. He was issued a third-class medical certificate on February 9, 2011, with the limitation that he must wear corrective lenses. The pilot’s logbook was recovered, and had 1,537.4 hours of flight time recorded, with the most recent entry dated February 17, 2011, and a flight review endorsement dated February 16, 2011. METEOROLOGICAL INFORMATION Lockheed Martin Flight Service has no record of the pilot receiving weather briefing services or accessing DUATS (Direct User Access Terminal Service) to view weather or file a flight plan. The surrounding area was documented utilizing Meteorological Aerodrome Reports (METARs) and special reports (SPECI) provided by Automated Surface Observation Systems (ASOS) and Automated Weather Observation Systems (AWOS) installed at airports surrounding the area. The closest weather reporting facility to the accident site was from Barstow-Daggett Airport (KDAG), Daggett, California, located approximately 16 miles west-northwest at an elevation of 1930 feet. The airport had an ASOS and was listed as having a 15-degree east magnetic variation. The following conditions were reported near the time of the accident: Daggett (KDAG) weather at 1451 PST (2251Z), automated, surface wind from 250 at 36 knots with gusts to 46 knots; visibility unrestricted at 10 miles, sky clear below 12,000 feet; temperature 17 Celsius (C); dew point -4 C; and altimeter 29.74 inches of mercury (Hg). Remarks: automated observation system, peak wind from 250 at 52 knots recorded at 1413 PST; sea level pressure 1005.6-hPa; temperature 17.2 C; dew point -3.9 C; with the thunderstorm sensor inoperative. Peak wind gusts over 50 knots were recorded surrounding the period with the maximum wind noted at 56 knots. The next closest station was Bicycle Lake Army Airfield (KBYS), Fort Irwin, California, located approximately 3 miles northeast of Barstow and 31 miles north-northwest of the accident site at an elevation of 2,350 feet. The following conditions were reported surrounding the accident period: Bicycle Lake Army Airfield (KBYS) at 1455 PST, wind from 230 at 25 knots with gusts to 42 knots; visibility 10 miles, sky clear below 12,000 feet; temperature 14 C; dew point -6 C; altimeter 29.69 inches of Hg. Remarks: automated observation system, peak wind from 220 at 47 knots occurred at 1408 PST; lightning distant northeast; sea level pressure 1005.2-hPa; temperature 14.2 C; dew point -5.9 C; maintenance needed. Edwards Air Force Base (KEDW), located approximately 72 miles west of the accident site at an elevation 2,311 feet, had a military weather observer augmenting the ASOS at the airport. Strong gusting winds were also reported surrounding the period with blowing dust and sand at and in the vicinity of the station, rapid changes in pressure, and reports of altocumulus standing lenticular (ACSL) clouds associated with mountain wave activity prior to the accident. Wind conditions at 1455 were from 270 degrees at 23 knots gusting to 43. Regional Wind Data A plot of local wind data for the time period surrounding 1500 PST was generated from the Mesowest plot of local Remote Automated Weather Stations (RAWS) and NWS METAR reports across the region. Wind direction is provided by the pendant with the sustained wind speed on the left of the station and gust to the right in miles per hour (mph). The image depicts a band of westerly winds sustained at 40 mph or more concentrated in the vicinity of the accident site with wind gusts to 56 mph. The highest wind was reported north of Edwards Air Force Base at Jawbone with a wind gust to 73 mph, and at Squaw Springs at 66 mph. Upper Air Data The atmosphere was conditionally unstable below approximately 13,000 feet and supported thermal activity to that height and became more stable with height, with the Lifted Index (LI) 12 of 3.2, which ch