Needles, CA, USA
N647C
Daughters T18C
The airplane broke up in flight and impacted terrain. A search and rescue (SAR) crew located the airplane after the issuance of a family concerned alert notification (ALNOT). A review of the radar data showed a target consistent with the accident airplane at a mode C reported altitude of 12,300 feet mean sea level (msl) at 1103:45. The target continued in a westerly direction, and at 1104:56, the mode C altitude was 5,000 feet, which equates to a calculated 9,400 feet per minute (fpm) rate of descent. The last target was 12 seconds later at 1105:08, at a mode C altitude of 3,300 feet. The primary wreckage consisted of the fuselage, right wing, landing gear, and engine. The left wing was 1 mile west of the main wreckage on the eastern slope of a mountain peak. The left main wing spar separated from the inboard stub section, with compression wrinkles noted in the webbing of the outboard left main wing spar. The lower spar cap had a smooth fracture surface and the upper spar cap had an angular fracture surface, features consistent with the wing failing in negative aerodynamic loading. The right wing main spar remained attached to the stub carry through spar and the webbing was also wrinkled. Analysis of the meteorological conditions disclosed that a strong west-southwesterly jet stream was advecting mid- and high-level moisture from off Baja, California, into the southwestern United States. Light rain and rain showers were occurring over southern California and were associated with this moisture advection. The closest weather reporting facility was somewhat downstream of the accident location with respect to cloud movement. Observations made from the facility during the hour before the accident indicated that the cloud ceiling lowered during that period to around 11,000 feet. One Pilot Report (PIREPs) near Blythe, California, confirmed the presence of towering cumulus (TCU) in the area. Radar and satellite data indicated that convective clouds were in the accident area and rapidly increasing in altitude with very strong vertical motion around the accident time. In addition, deviations in the accident airplane's mode C altitude data just before the accident indicates that strong up- and downdrafts were present in the area. Strong jet stream winds near 100 knots were present in the area about the height of the convective clouds. Therefore, isolated strong convective downdrafts were possible in the area of the breakup. While proceeding westbound, the airplane was probably in the vicinity of the northern edge of a rapidly developing convective buildup. The pilot probably encountered moderate to severe turbulence due to strong updrafts and downdrafts just before the accident.
HISTORY OF FLIGHT On November 11, 2003, about 1105 Pacific standard time (PST), an experimental Daughters Thorpe T18C, N647C, broke up in flight and impacted terrain in the Turtle Mountains Wilderness area near Needles, California. The pilot/owner operated the airplane under the provisions of 14 CFR Part 91. The airplane was destroyed in the accident sequence. The private pilot and one passenger received fatal injuries. Visual meteorological conditions prevailed for the cross-country flight that departed the Glendale Municipal airport (GEU), Glendale, Arizona, at 1015 mountain standard time. No flight plan had been filed. The flight was destined for the Santa Maria Public/Captain G Allan Hancock Field, (SMX), Santa Maria, California. A search and rescue (SAR) crew located the airplane at 0837 on November 12, 2003, after the issuance of a family concerned alert notification (ALNOT). A SAR printout of radar data showed a target at a mode C reported altitude of 12,300 feet mean sea level (msl) at 1103:45 PST. The target continued in a westerly direction, and at 1104:56, the mode C altitude was 5,000 feet , with a 9,400 feet per minute (fpm) rate of descent based on computed time and altitude differences between the target returns. The last target was 12 seconds later at 1105:08, at 34 degrees 24.23 minutes north latitude and 114 degrees 44.45 minutes west longitude. The reported mode C altitude was 3,300 feet. PERSONNEL INFORMATION The pilot logbook excerpts provided to the National Transportation Safety Board investigator-in-charge (IIC) contained entries from January to August 2003. The pilot logged 68 hours with 43 in the T-18. They indicated a total time of 1,173 hours, 4 of which were in multiengine airplanes. AIRCRAFT INFORMATION A captain's logbook found in the wreckage had no entries between 1995 and January 2003. The logbook contained an entry for the replacement of the skin on the top right aileron and bottom left aileron. It also noted installation of a rebuilt magneto. There was no entry for a conditional inspection. WRECKAGE AND IMPACT A San Bernardino County sheriff's deputy examined the crash site. He noted that the site was about 24 nautical miles (nm) southwest of Lake Havasu, Arizona. The terrain was rocky, sandy desert with minimal desert shrubbery. The elevation was about 1,620 feet msl. The deputy noted that the primary wreckage consisted of the fuselage, right wing, landing gear, and engine. The main wreckage came to rest inverted on a westerly orientation. The debris field encompassed an area approximately 30 feet in diameter. He observed compression damage to the fuselage. He reported that the vertical stabilizer was attached to the fuselage, but bent toward the starboard side of the airplane. Both horizontal stabilizers remained attached, and exhibited compression damage. The canopy was crushed with the remnants located under the fuselage wreckage. The right wing partially separated and exhibited vertical crush damage; the wing tip completely separated. The engine separated and was 20 feet west of the fuselage. The wooden propeller, hub, and nose cone remained attached to the engine, but about 12 inches of both propeller blade tips were missing. The left wing was 1 mile west of the main wreckage on the eastern slope of a mountain peak. The left flap separated from the left wing, and was 200 yards west of the main wreckage. MEDICAL AND PATHOLOGICAL INFORMATION The San Bernardino County Coroner completed an autopsy. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. They did not perform tests for carbon monoxide or cyanide. The report contained the following findings for tested drugs: chlorpheniramine detected in liver and lung, diphenhydramine present in liver; phenylpropanolamine detected in liver and lung; pseudoephedrine detected in lung and liver; and ephedrine detected in liver and lung. The report contained the following findings for volatiles: no ethanol detected in liver; 19 (mg/dL, mg/hg) ethanol detected in lung, 9 (mg/dL, mg/hg) acetaldehyde detected in liver; 5 (mg/dL, mg/hg) acetaldehyde detected in lung. METEOROLOGY A Safety Board meteorologist prepared a factual report and pertinent parts follow. Surface and Upper Air Analysis Charts Surface and upper air analysis charts indicated variable cloud ceilings and no fronts or significant pressure features over Arizona and southern California. Station plots and isobars indicated a low-pressure area off the southern California coastline. Also, the charts showed southwesterly winds over Arizona at 10-30 knots, and variable southerly and southeasterly winds over southern California at 10-20 knots. The 0 degree Celsius isotherm was shown extending from near San Diego, California, through the vicinity of Flagstaff, Arizona. Surface Observations The following are pertinent surface weather observations for Needles Airport, located 23 nautical miles northeast of the accident site at a field elevation of 983 msl. It had a non-augmented Automated Surface Observing System (ASOS). An aviation routine weather report (METAR) issued at 0956 PST stated: winds from 360 degrees at 10 knots; visibility 10 miles; skies, few clouds at 11,000 feet; temperature 18 degrees Celsius; dew point 7 degrees Celsius; altimeter 30.14 inches of mercury. A METAR at 1056 stated: wind 350 degrees at 11 knots; visibility.10 miles; sky condition, broken at 9,500 feet; temperature.19 degrees Celsius; dew point.07 degrees Celsius; altimeter setting.30.12 inches of mercury. A METAR at 1156 stated: wind, 350 degrees at 9 knots; visibility.10 miles; sky condition, scattered at 9,000 feet; temperature.19 degrees Celsius; dew point.07 degrees Celsius; altimeter setting.30.10 inches mercury. GOES-10 (Geostationary Operational Environmental Satellite-10) GOES-10 (Geostationary Operational Environmental Satellite-10) digital data centered on the accident area were obtained through NOAA/NCDC and displayed on a NTSB McIDAS workstation. The nominal resolutions of the visible and infrared data were 1 and 4 kilometers. According to McIDAS software, the cloud-top radiative temperature at and/or near the accident location taken from the 1100 data was approximately 239 degrees Kelvin (-34 degrees Celsius). The visible and infrared images for the nominal time of 1030 corresponded to the beginning portion of N647C's plotted ground track depicted in the Meteorological Factual Report. The visible and infrared images for the nominal time of 1045 corresponded to the middle portion of N647C's plotted ground track depicted in the Meteorological Factual Report. The visible and infrared images for the nominal time of 1100 (the satellite imaged the accident area at 1103:57) corresponded to the last few minutes of N647C's flight. National Weather Service WSR-88D Data The closest WSR-88D radar was ESX (355 degrees at 78 nm). Assuming standard refraction, the height of the ESX radar beam over the accident location was calculated for several antenna elevation angles. The meteorological factual report contained plots of the 0.5-degree Reflectivity Product. Pilot Reports (PIREPs) No PIREPs were specific to the accident area. However, PIREPS generally indicated variable cloud tops with light to moderate icing in clouds. Also, light to moderate turbulence was reported above 10,000 feet msl with most moderate reports above 16,000 feet msl. A PIREP reported near Blythe confirmed the presence of towering cumulus (TCU) in the area. Winds and Temperatures Aloft Model sounding data indicated that light northeasterly winds were present in the accident area below 9,000 feet msl. Above that level, winds veered to the southwest increasing to over 50 knots above 19,000 feet msl. The data indicated a strong southwesterly jet stream aloft with winds exceeding 100 knots above 29,000 feet msl. Data showed that the freezing level was about 10,000 feet msl. Aviation Area Forecast (FA) The FA pertinent to southern California predicted scattered to broken clouds at 10,000 feet layered to FL250 and isolated light rain showers for the accident area. TESTS AND RESEARCH The Safety Board IIC supervised examination of the wreckage by a mechanic and the Federal Aviation Administration at Aircraft Recovery Services, Littlerock, California, on November 19, 2003. The engine was a TMX Experimental Aircraft Engine marketed by Teledyne Mattituck Services; they built it using parts from Engine Components, Inc. The left side of the engine sustained mechanical damage. The numbers 2 and 4 cylinder heads were displaced from their respective barrels. The left magneto and carburetor were displaced from their mountings. The mechanic did not note any evidence of preimpact catastrophic mechanical malfunction or fire. He removed the top spark plugs for cylinders no. 1 and no. 3. They did not exhibit any mechanical damage, and were light gray. All of the top plugs were Denso W27ESR-U automotive type, and the bottom plugs were Champion aviation type. The mechanic observed normal combustion signatures with no evidence of detonation or foreign object damage in the combustion chambers of the no. 2 and no. 4 displaced cylinder heads. He made the same observations for cylinders no. 1 and no. 3 using a lighted borescope. He reported that the gas path and combustion signatures were consistent with normal operation. He noted significant ductile bending of the exhaust system components. Investigators were unable to obtain full rotation of the crankshaft. They established gear train continuity through limited rotation of the crankshaft. The mechanic examined internal components with a borescope inserted into the case. He saw no evidence of lubrication depravation or contamination. The camshaft was intact and the lobes' shapes appeared normal. The ignition system consisted of a magneto on the left side of the engine, and a Light Speed Engineering, CDI Hall Effect Module trigger assembly on the right side. A high-energy coil was on top of the engine case; it connected to each of the top automotive style plugs. The magneto connected to the bottom aviation style plugs. Both ignition harnesses were destroyed. The magneto sustained mechanical damage. The impulse coupler drive was intact and secure. The drive functioned with manual rotation, and produced spark at all four terminal. The throttle and mixture controls remained attached to the carburetor. The carburetor fuel inlet screen was properly installed and free of contamination. There were no visible contaminants in the bowl. The float assembly remained secure at the mounting and was not damaged. The engine fuel lines were secured to their respective fittings. The examination of the airplane revealed that the outboard 5-foot portion of the left wing had separated. The wing assembly consisted of an outboard wing panel, which was joined to a stub wing fuselage carry through member. The main wing spar separated from the inboard stub section. The outboard left main wing spar showed wrinkles in the webbing. The lower spar cap had a smooth fracture surface. The upper spar cap had an angular fracture surface. The right wing main spar remained attached to the carry through spar. The webbing was wrinkled. The main landing gear remained attached to the fuselage. Both the empennage and the engine separated from the aircraft; however, both were at the main wreckage site. The tail remained attached to the empennage. Investigators noted no other mechanical anomalies.
the pilot's continuation of a visual flight rules (VFR) flight into an area of adverse weather, which resulted in an encounter with moderate to severe turbulence and in-flight breakup of the airplane.
Source: NTSB Aviation Accident Database
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