Aviation Accident Summaries

Aviation Accident Summary WPR11FA155

Newberry Springs, CA, USA

Aircraft #1

N122B

MUSE KR2

Analysis

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.

Factual Information

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 characterized the sounding as stable. The sounding wind profile indicated a surface wind from 255 degrees at 10 knots with little directional variation with height through 18,000 feet and slowly increasing wind speeds with height, with westerly winds in excess of 50 knots above 17,000 feet. The level of maximum wind was from 310 degrees at 103 knots and located below the tropopause at 34,000 feet. A low-level wind maximum was identified at 9,500 feet with wind from 245 at 28 knots, which resulted in a strong local vertical wind shear capable of producing a high probability of 100 percent probability of moderate or greater turbulence in the layer. The mean 0 to 6 kilometer wind was from 295 at 33 knots. Pilot Reports There were numerous pilot reports of encounters with moderate to severe turbulence below 13,000 feet with one report of extreme turbulence was received from a pilot operating a Cessna Citation business jet at 2,000 feet in the vicinity of Palm Springs. The Citation pilot also reported encountering low-level wind shear. One of the moderate-to-severe turbulence reports came from a Boeing 737 air carrier jet crew that reported the encounter at 100 feet agl on approach into Burbank. Several other pilots reported encountering mountain wave activity with updrafts and downdrafts from 1,500 to 2,500 feet per minute (fpm) and unusually strong low-level winds. A pilot operating a Cessna Caravan C208 single engine turboprop reporting a 125-knot headwind northbound near the coastal mountain range at 10,000 feet west of the accident site. In-Flight Weather Advisories AIRMET Tango for turbulence, strong winds, and low level wind shear was valid in the area of the accident until 2000 PST. A complete weather study is contained in the official docket of this investigation. WRECKAGE AND IMPACT The terrain in the vicinity of the wreckage consisted of a shallow slope, dry desert sand and rock, with evidence of water drainage cuts into the slopes creating small fingers of raised terrain. The area was sparsely populated by desert scrub and sagebrush. The airplane’s initial point of ground impact consisted of a 5-foot by 8-foot patch of disturbed earth that contained fragments of propeller and engine chin cowling fiberglass. The engine core traveled 185 feet on a bearing of 052 degrees from this point; oil residue and cockpit debris was also distributed along that same bearing. A 4-foot by 3-foot area of disturbed earth was identified 74 feet directly behind the initial airplane impact and contained no airplane debris, but did contain tissue and bone fragments. The cockpit was completely destroyed. Pieces of instrument panel and flight instruments, along with propeller shards were distributed along the line between the initial impact point and the engine core. Both wings were located along a 109-degree bearing line from the cockpit and engine debris (initial impact point). The right wing was 213 feet from the initial impact point and the left wing was 372 feet from the same point. The right wing’s tip was fragmented. No leading edge damage, wing surface damage, or marks, were evident; the aileron had separated from the trailing edge. The wing separated from the fuselage at the wing root; the wing attachment fitting was present on the wood wing spar with the attach bolts in place. The left wing exhibited no leading edge or surface skin damage except for a chordwise crack was located about 3 feet inboard from the wing tip, and a 2-foot by 3-foot section of the wing aft of the wing spar was not present. The wing had separated from the fuselage at the wing root, and the wing attachment fitting was on the wood wing spar with the attach bolts in place. The aileron had separated from the trailing edge of the wing. Both the left and right ailerons were located in the vicinity of the left wing. The rudder was located on a bearing line of 342 degrees, 150 feet from the impact point. The upper third of the vertical stabilizer (approximately 2-foot-long section) was located on a bearing line of 090 degrees, 1,820 feet from the impact point. An 8-inch piece of rudder skin was located along the same bearing line, 2,661 feet from the impact point, and was the farthest piece of debris located. The forward wood spar of the vertical stabilizer had split along the wood grain and separated. The aft wood spar of the vertical stabilizer had broken across the grain at the upper rudder hinge bolt holes that had been drilled into the spar. Fragments of skin consistent with the wing gap seal were located on a bearing of 090 degrees, 920 feet from the impact point, along with a fragment of elevator skin. Fragments of the horizontal stabilizer were located along a bearing line of 107 degrees, at 500 feet. Examination of the flight controls revealed all control cable ends were attached to fragments of control horns. All cable separations were broomstrawed consistent with overload, and control connection horns were separated in bending overload. The left aileron bell crank remained mounted to the aft spar on the left wing, the right aileron bell crank was located on section of aft wing carry through spar that had separated from the wing and fuselage. Aileron cable ends and turnbuckles were attached to the control stick and safety wired. The elevator cable connections attached to the control stick by two vertical tabs that had separated from the stick by overload. Rudder cables were attached to the rudder bar, and the cable ends were attached to fragments of the rudder horn. The engine had fragmented due to impact forces, and was covered in oil. Both the left and right valve heads had separated from the piston cylinders. The piston cylinders had separated from the engine case. All valves, valve springs, and rocker arms were present on the cylinder heads. Spark plugs were present, all gaps were similar, and no mechanical damage was evident. All four cylinders were accounted for and no mechanical damage was evident. Piston faces and valves exhibited light gray combustion deposits. All four pistons were attached to the crank shaft via the connecting rods. The crankshaft was slightly rotated by hand from the propeller flange and movement was observed by all four pistons through to the accessory section at the aft end of the engine. The magneto was fragmented and could not be tested. The oil suction screen was clear of debris. The exhaust manifold was attached to both sets of cylinder heads, and exhibited ductile deformation. The carburetor had separated from the induction system, but the throttle cable remained in place on the carburetor. The carburetor fuel inlet had separated at the fitting, and the mixture cable was not attached to the mixture lever. MEDICAL AND PATHOLOICAL INFORMATION An autopsy was performed on the pilot on March 9, 2011, by the San Bernardino County Sheriff’s Department, Coroner Division. The autopsy finding cause of death was “massive body fragmentation.” Forensic toxicology was performed on specimens obtained from the pilot by the FAA Forensic Toxicology Research Team CAMI, Oklahoma City, Oklahoma. The toxicology report states that tests for carbon monoxide and cyanide were not performed. No ethanol was detected in muscle. Atenolol was detected in muscle and dextromethorphan was detected in muscle.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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