History of Flight
On August 30, 2012, about 1615 mountain daylight time, an Aircraft MFG & Development Company CH 2000, registration N651AM, was substantially damaged when it impacted terrain while in the traffic pattern at Nephi Municipal Airport (U14), near Nephi, Utah. The airplane was registered to private individuals and operated by the pilot under Title 14 Code of Federal Regulations Part 91. The certified flight instructor (CFI) and private pilot receiving instruction sustained fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight. The local flight originated from Provo Municipal Airport near Provo, Utah, about 1500.
Witnesses located adjacent to the accident site observed the airplane on a southerly heading south of U14 before it turned left to a northerly heading at an altitude of about 150 feet above ground level. Multiple witnesses reported that the airplane seemed to be traveling at a slow speed when it suddenly pitched downwards and descended into the ground. One witness stated that prior to the sound of impact, the engine seemed to be at a high power setting. Witnesses further stated that at the time of the accident, a thunderstorm with strong wind, heavy rain, and lightning were present in the area.
Personnel Information
The flight instructor, age 45, held a commercial pilot certificate with airplane single-engine land and instrument airplane ratings, and a flight instructor certificate with airplane single-engine land and instrument ratings. A second-class airman medical certificate was issued on April 16, 2012, with no limitations. He reported 950 total flight hours on his most recent medical certificate application.
The pilot receiving instruction, age 59, held a private pilot certificate with an airplane single-engine land rating, issued on August 29, 2012, based on his Canadian private pilot certificate issued on February 19, 2011. A third-class airman medical certificate was issued on March 23, 2010, with the limitation "glasses must be worn." His logbook showed a total of 94.8 flight hours as of March 12, 2012.
Aircraft Information
The two-seat, low-wing, fixed-gear airplane, serial number 20-1021, was manufactured in 2003. It was powered by a Lycoming O-235-N2C engine, serial number L-255755-15, rated at 116 horsepower, and equipped with a Sensenich fixed-pitch propeller. The airplane was recently purchased by the pilot receiving instruction and another individual.
Review of maintenance logbooks revealed an annual inspection on August 17, 2012, at a tachometer time of 215.7 hours. An export control examination by an FAA designated airworthiness representative on August 22, 2012, showed a tachometer time of 216.0 hours and a hobbs/airplane total time of 242.5 hours. The tachometer indicated 217.6 hours at the accident site.
Meteorological Information
An NTSB staff meteorologist prepared a factual report. The National Weather Service Surface Analysis Chart for 1500 showed a low pressure system over Wyoming with a cold front extending southwestward into northern Colorado and a stationary front into Utah and Nevada. Station models near the accident site reported north-northwest wind at 10 to 15 knots, scattered clouds, temperatures 88-89°F, and dew points 45-48°F.
The NWS Storm Prediction Center's Convective Outlook expected a general risk of thunderstorms. Regional radar mosaic at 1615 showed scattered weather echoes over the region, with one area over Nephi with maximum reflectivity near 45 dBZ. The accident site was under that area.
Nephi Municipal Airport (U14) has an Automated Weather Observation System (AWOS) that does not disseminate observations to the FAA or NWS. MesoWest data from 1559 reported westerly wind from 260° at 6 knots gusting to 19 knots, scattered clouds at 11,000 feet, temperature 88°F, dew point 43°F, relative humidity 21%, altimeter 29.97 inHg, and calculated density altitude 8,029 feet.
At 1659, wind had shifted to east from 080° at 12 knots gusting to 19 knots, with a 6°F temperature decrease, rising dew point, falling then rising pressure.
Sounding parameters indicated a warm dry low-level environment with Lifted Index -0.9 (conditionally unstable favoring scattered high-based thunderstorms), Vertical Totals index 37.1 (potential for strong thunderstorms), WINDEX microburst potential 37 knots, GOES Hybrid Microburst Index 29 (strong potential for dry microbursts), and Microburst Day Potential Index 0.3 (low potential). Gust potentials ranged from 54 to 57 knots.
Wind profile showed surface wind from 345° at 8 knots, backing to southwest with height.
Provo observations at 1600 placed them on the edge of clouds with lightning detected to the southeast. Rain showers were reported from cumulus congestus clouds. Delta, Utah reported cumulonimbus in all quadrants with blowing dust and rain showers after the accident. Price, Utah reported lightning to the west before the accident and convective clouds.
WSR-88D base reflectivity images from 1610 to 1623 showed scattered echoes, with a defined cell immediately south of the airport and over the accident site moving northeastward. Echoes were moderate to strong intensity.
Archived lightning data from 1600 to 1620 identified 7 in-cloud and cloud-to-ground flashes within 50 miles of the accident site. No cloud-to-ground lightning was detected within 15 miles. In-cloud lightning is typical during towering cumulus or cumulus congestus stages. The detection confirms the area of weather encountered was associated with a cumulonimbus cloud, though low-topped without defined anvil outflow.
Airport Information
Nephi Municipal Airport (U14) is a non-towered airport in class G airspace with a field elevation of 5,022 feet msl. It has one asphalt runway (17/35), 6,300 feet long and 100 feet wide with a 0.7% negative gradient. The standard traffic pattern for runway 17 uses left turns.
Wreckage and Impact Information
The airplane impacted terrain about 1.7 miles southeast of U14 at 4,867 feet msl. The aft fuselage and empennage partially separated and came to rest inverted; the forward fuselage, wings, and engine were upright. Main wreckage rested on a magnetic heading of about 326°, within a 50-foot radius.
The first identified point of contact (FPIC) was a ground scar about 1 foot wide and 12 feet long, containing fragments of green lens material from the right wing navigational light. A deeper scar 4x4 feet contained plexiglass and fiberglass. Main wreckage came to rest about 8 feet beyond the FPIC. The right main landing gear wheel assembly separated and was found between the FPIC and main wreckage.
The engine, firewall, and instrument panel sustained impact damage, distorted forward of the wing leading edges. A section of the instrument panel separated.
Both wings remained partially attached; ailerons and flaps were attached. Leading edges were crushed aft and upwards. The outboard portion of the right wing was crushed upward from mid-span with 45° crush angles.
The cabin and fuselage were partially consumed by fire. Both wing tanks were crushed and torn open.
Flight control continuity was established from cockpit controls to all primary flight controls.
The engine was partially attached; the mounting assembly exhibited impact damage. The exhaust assembly was crushed and partially separated. The right magneto, vacuum pump, oil filter housing cap, and oil dipstick separated. The crankshaft rotated by hand through the upper accessory gear; cylinder compression and valve continuity were obtained on all four cylinders. Both magnetos produced spark. Top spark plugs showed normal operating signatures.
The propeller remained attached with "S" bending curled opposite rotation; one blade had leading edge polishing in the outboard 8-10 inches, the other had a slight aft bend from 8 inches inboard of the tip.
Medical and Pathological Information
The Utah State Medical Examiner conducted autopsies on August 31, 2012, for both the CFI and the pilot receiving instruction. The cause of death for each was determined to be "blunt force injuries."
The FAA's Civil Aeromedical Institute performed toxicology tests on both pilots; results were negative for carbon monoxide, cyanide, volatiles, and drugs.