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On October 11, 2008, at 1702 mountain daylight time, a Maule MXT-7-180A airplane, N4257C, entered a thunderstorm and impacted terrain shortly after takeoff from Dona Ana County Airport (5T6), Santa Teresa, New Mexico. The private pilot and private pilot rated passenger were fatally injured. The airplane was destroyed. The personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91 without a flight plan. Instrument meteorological conditions prevailed at the time of the accident. The flight was originating at the time of the accident with Springerville Municipal Airport (D68), Springerville, Arizona, as the intended destination.
The two pilots departed Glendale Municipal Airport (GEU), Glendale, Arizona, and arrived at 5T6 the day of the accident to visit the "Land of Enchantment RV Fly-in" being held there. Witnesses saw the airplane taxi and perform an intersection takeoff on Runway 28 directly towards an isolated thunderstorm immediately off the departure end of the runway. The airplane appeared to climb to 150 to 200 feet above the ground before disappearing from view in the storm. One witness stated the airplane wings were rocking back and forth and the pilot appeared to be having difficulty controlling the airplane just before it went out of view. Five to ten minutes later, after the storm moved past, smoke was seen rising approximately one mile west of the airport.
The pilot, age 46, held a private pilot certificate with ratings for airplane single-engine land and airplane multiengine land. He was not instrument rated. His last Federal Aviation Administration (FAA) second-class medical certificate was issued on April 19, 2006, with no limitations.
An examination of the pilot's logbook indicated an estimated total flight time of 1,755 hours; of which 1,293 hours were in the accident airplane. He logged 57.8 hours in the last 90 days and 11.1 hours in the last 30 days. His last noted flight review was completed May 4, 2008.
The passenger, age 43, held a private pilot certificate with a rating for airplane single-engine land. He was not instrument rated. His last Federal Aviation Administration (FAA) third-class medical certificate was issued on November 21, 2001, with no limitations.
No pilot logbooks were found for the passenger. He indicated 140 total hours on his last application for medical certification, dated November 21, 2001.
The 1999-model Maule MXT-7-180A, serial number 21070C, was a high wing, fabric covered airplane, with a fixed tricycle landing gear, and was configured for four occupants. The airplane was powered by a direct drive, horizontally opposed, carbureted, air-cooled, four-cylinder engine. The engine was a Lycoming O-360-C4F, serial number L-36632-36A, rated at 180 horsepower at 2,700 rpm, and was driving a two-bladed, metal, Sensenich propeller.
The last airplane and engine inspections were an annual type, completed on December 15, 2007, at 850.9 total hours.
The airplane was fueled with 29.4 gallons of aviation fuel at 5T6 the day of the accident.
A special weather observation was taken from the national weather service station (KEPZ) located at 5T6 at 1709: winds 300 degrees at 14 knots, gusting to 31 knots, 10 miles visibility, broken clouds at 6,000 feet, overcast at 25,000 feet, thunderstorm within 10 miles northwest moving northeast at 35 miles per hour. A review of collected weather data indicate a thunderstorm moved west of the airport within one mile at 1702. At 1702 NEXRAD radial wind velocity images depicted a divergent wind pattern over the accident site with a shear of greater than 60 knots between the inbound and outbound wind components.
Thunderstorm reflectivity is normally displayed in decibels (dBZ), and is a general measure of echo intensity. The Federal Aviation Administration (FAA) Advisory Circular AC 00-24B titled "Thunderstorms" dated January 2, 1983, defines echo intensity levels and potential weather phenomena associated with those levels.
The following table defines Video Integrated Processor (VIP) types and severity of weather phenomena associated with each VIP level. Each VIP level has a corresponding dBZ range.
VIP Level 1 <5 - 14 dBZ
VIP Level 2 15 - 29 dBZ
VIP Level 3 30 - 39 dBZ
VIP Level 4 40 - 44 dBZ
VIP Level 5 45 - 49 dBZ
VIP Level 6 50 and greater dBZ
VIP Level is 1 "weak" and VIP Level 2 is "moderate", indicating light to moderate turbulence is possible with lightning. VIP Level 3 is "strong" and severe turbulence is possible with lightning. VIP Level 4 is "very heavy" and severe turbulence is likely with lightning. VIP Level 5 is "intense" with severe turbulence, lightning, hail likely, and organized surface wind gusts. VIP Level 6 is "extreme" with severe turbulence, lightning, large hail, extensive surface wind gusts and turbulence.
KEPZ WSR-88D base reflectivity images for 0.5 degree elevation scans were completed at 1657, 1702, and 1706. The images depict an area of extreme intensity echoes with reflectivity exceeding 55 dBZ moving to the northeast and passing directly over the accident site at the approximate time of the accident.
The KEPZ composite reflectivity images for 1657, 1702, and 1706 show maximum reported echo intensity between 61 and 63 dBZ within the weather complex. The images depict an organized, intense convective system moving over the accident site with echo intensity between 50 and 55 dBZ between 1647 and 1702.
Convective Significant Meteorological Information (SIGMET) 42C was current and applied to the accident site at the time of the accident. It warned of an area of thunderstorms moving from 220 degrees at 10 knots with maximum tops to 43,000 feet. The advisory implied severe and greater turbulence, low-level wind shear, and local instrument meteorological conditions.
No evidence was found indicating either the pilot or passenger had obtained weather information or a weather briefing prior to departure.
WRECKAGE AND IMPACT INFORMATION
Examination of the airplane revealed the fuselage frame was mostly intact aft of the front cockpit. The fuselage and all interior materials were mostly burned, with fabric remnants remaining only on the empennage. Both wings were attached to the fuselage and had damage from fire near the wing root area. Control cable continuity from the cockpit was verified to all control surfaces. One propeller blade was partially embedded in the ground and both blades showed chord-wise scratching and leading edge impact marks.
MEDICAL AND PATHOLOGICAL INFORMATION
The Office of the Medical Investigator, The University of New Mexico, located in Albuquerque, New Mexico, performed an autopsy on the pilot on October 11, 2008. The cause of death was attributed to multiple blunt force injuries.
The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the pilot. Testing for carbon monoxide and cyanide were not conducted. No Volatiles or Drugs were detected.
The Office of the Medical Investigator, The University of New Mexico, located in Albuquerque, New Mexico, performed an autopsy on the passenger on October 11, 2008. The cause of death was attributed to multiple blunt force injuries.
The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the passenger. Testing for carbon monoxide and cyanide were not conducted. The following Volatiles and Drugs were detected:
- 67.3 (ug/ml, ug/g) acetaminophen detected in urine.