Aviation Accident Summaries

Aviation Accident Summary ERA09FA311

Clintwood, VA, USA

Aircraft #1

N6628U

MOONEY M20D

Analysis

Witnesses in the local area reported that they watched the airplane descend in a circle to get beneath clouds before continuing in its original direction. The airplane subsequently passed in and out of clouds before disappearing from sight. Another witness observed the airplane flying in a northerly direction toward a mountain ridge. The airplane then flew into a fog bank at the top of the mountain, and there was the sound of a crash. Examination of the wreckage did not reveal mechanical or flight control anomalies that may have contributed to the accident. The pilot had been under substantial stress in the months leading up to the accident, and had been complaining of symptoms of shoulder pain 1 month prior to the accident. He had been diagnosed with myasthenia gravis, a neuromuscular disorder, approximately 2 years prior to the accident, but was apparently in complete remission from the disease. It is unlikely that the myasthenia gravis was related to the accident, although the pilot may have been distracted by symptoms of stress or back pain.

Factual Information

HISTORY OF FLIGHT On May 29, 2009, about 1345 eastern daylight time, a Mooney M20D, N6628U, collided with mountainous terrain near Clintwood, Virginia. The private pilot was killed and the airplane was substantially damaged. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91, and no flight plan was filed for the visual flight rules flight. The flight originated at Elizabethton Municipal Airport (0A9), Elizabethton, Tennessee, about 1311. According to the Virginia Department of Emergency Management, the pilot's wife reported that the pilot departed from 0A9 enroute to Ashland Regional Airport (DWU), Ashland, Kentucky. When he did not arrive, and was overdue, she reported him missing. A witness near the accident site observed the airplane flying in a northerly direction towards a mountain ridge (Pine Mountain). He said during that time "there was a lot of fog at the top of the Mountain." The witness soon lost sight of the airplane, but could still hear the engine running. He then heard the engine make a sputtering noise, followed by a loud crash. At that point, he drove his car around the base of the mountain to see if there was any smoke. When he did not see any smoke, he thought “everything was fine.” The following day he heard a report that a small airplane was missing. He subsequently contacted the local authorities and assisted them by directing them to the location where the missing airplane had crashed. According to the Civil Air Patrol (CAP) incident commander, after receiving notification of the missing airplane they mobilized airplanes to assist in the search and recue. They interviewed witnesses in the local area who reported that they watched as the airplane descended in a circle to get beneath clouds before continuing in its original direction. They continued by saying that the airplane passed in and out of clouds before disappearing from sight. The witnesses were located approximately 3 miles from were the airplane was located. A review of radar data provided by Federal Aviation Administration (FAA) Air Traffic Control personnel indicated that the airplane departed 0A9 about 1311, with a 1200 transponder code. Radar tracked the airplane along its entire flight course. Approximately 32 minutes into the flight the airplane was observed in a slow descending turn from 5,900 feet. The airplane reversed its course and continued to descend before turning back on its original course direction. At that time, the airplane was at an altitude of 2,800 feet, and headed northerly until radar contact was lost. PERSONNEL INFORMATION The pilot, age 57, held a private pilot certificate, with ratings for airplane single-engine land and instrument airplane. According to the FAA Airman's Certification branch his certificate was updated for his instrument rating on April 13, 1984, with 22 hours of instrument instruction. The pilot's most recent FAA third-class medical certificate was issued August 28, 2007, with limitations for lenses for distant vision. The pilot reported 900 hours total flight time on his last FAA medical application; however, his logbook was not available for review, and a determination of his total flight hours could not be made. The pilot's airplane insurance application revealed that the pilot had a private pilot's license with IFR ratings. It also showed that he had 900 total time hours, 500 retract time, 10 hours in make and model, 66 hours in the last 12 months as of August 6, 2008. No hours were given for instrument time. According to the pilot's certified flight instructor his last recorded flight review with the pilot was on October 5, 2007, and he satisfactorily completed the flight review. AIRCRAFT INFORMATION The four-seat, low-wing, retractable gear airplane, serial number 123, was manufactured in 1963. It was powered by a Lycoming O-360, 180-horsepower engine and equipped with Hartzell three-bladed propeller. There were no aircraft logbooks available for review. According to the airport manager were the airplane was based, the pilot did his own maintenance and did not allow any one to work on his airplane. There were no records from any of the fixed base operators or local mechanics at the airport that worked on the pilot's airplane. METEORLOGICAL INFORMATION The 1355 weather observation for The Lonesome Pine Airport, Wise, Virginia, located 17 nautical miles southeast of the accident site, included the following: winds 290 degrees at 6 knots, visibility 10 miles, ceiling 1,100 feet broken, 1,800 feet broken, 9,000 feet broken, temperature 19 degrees Celsius (C), dew point 18 degrees C, and altimeter setting of 29.93 inches of mercury. According to the FAA Air Traffic Control Service personnel there were no records of any communication with the flight service station (FSS) or entries made in the direct user access terminal system (DUATS) prior to pilot's flight. WRECKAGE EXAMINATION The wreckage was located at the top of a mountain ridge in a heavily wooded area. Examination of the crash site revealed that the wreckage path was through tree tops and measured 200 feet in length. The airplane came to rest on the side of the ridge at approximately 2,600 feet mean sea level. The wreckage debris line headed 003 degrees magnetic and was approximately 3 miles from the airplane's last known radar position. All major components of the airplane were located at the accident site. Examination of the fuselage, cockpit, and cabin revealed that they were substantially damaged by impact forces and post-crash fire. The primary flight instrument panel with instruments was located at the crash site, and was impact damaged. All flight control surfaces were located at the wreckage site and were damaged from impact forces. Flight control cable continuity was traced from the cockpit section to all flight control surfaces, and all control cable separations were consistent with overload. The airframe and flight control system components revealed no evidence of preimpact mechanical malfunction or failure. The engine accessories and ignition leads were impact and heavily fire damaged. Valve train continuity was confirmed, and rotation of the crankshaft produced compression on all cylinders. Examination of the spark plugs revealed light gray deposits and normal wear. The oil screen and oil filter were examined, and were found absent of debris. Examination of the engine and system components revealed no evidence of preimpact mechanical malfunction. The propeller was separated from the crankshaft, and both propeller blades displayed chordwise scoring across the leading edge and forward face. One propeller blade exhibited an s-shaped bend, and the other propeller blade was bent and twisted mid-span to tip. Tree branches, 2 and 3 inches in diameter, were found within the debris path and observed severed cleanly in a diagonal linear pattern. MEDICAL AND PATHOLOGICAL INFORMATION The Commonwealth of Virginia, Office of the Chief Medical Examiner conducted the postmortem examination of the pilot on June 1, 2009. The reported cause of death was multiple blunt force injuries. Forensic toxicology was performed on specimens from the pilot by the Federal Aviation Administration Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated no ethanol was detected in the liver or muscle, and no drugs were detected in the liver. A review of the pilot’s personal medical records noted, on July 31, 2007 symptoms of “… muscle weakness … right eye ptosis [partial closure] with activity … fatigue at the end of the day.” On August 7, 2007, the records noted the diagnosis of “myasthenia gravis … new onset … prescribe: pyridostigmine bromide tablets 60 mg, ½ tablet with meals three times a day …,” and on August 21, 2007, the records noted “…medication is controlling his symptoms of MG … .” Surgery was documented to remove a “Thymoma, WHO type IB, minimally invasive” on September 18, 2007, and on December 17, 2007, the records noted that “…since the surgery, he has required less [pyridostigmine] .” On April 1, 2008, the records documented that “… the myasthenia gravis symptoms have resolved, he stopped the [pyridostigmine] ….” On April 29, 2009, the medical records noted that the pilot “… has some back pain … shoulder bilateral mild pain 2-4/10 at times … myasthenia gravis … asymptomatic since thymectomy … rheumatology consult ….” The pilot’s most recent application for 3rd class FAA Airman Medical Certificate, dated August 28, 2007, did not note the diagnosis of myasthenia gravis or the medication used to control the symptoms of the disorder. During a telephone conversation with the pilot’s daughter, she stated that the pilot was experiencing significant stress, including the death of his father about 6 months prior to the accident, and filing for divorce approximately 2 weeks prior to the accident.

Probable Cause and Findings

The pilot’s continued visual flight into instrument meteorological conditions, which resulted in controlled flight into terrain.

 

Source: NTSB Aviation Accident Database

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