ANDREWS, NC, USA
N5743N
Mooney M-20C
The flight was on an IFR flight plan between Richmond, Virginia, and Knoxville Downtown Island Airport, and according to transcripts of radio communications between N5743N and Atlanta ARTCC, the pilot cancelled his IFR flight plan to proceed VFR, (with Atlanta ARTCC flight following) to avoid icing conditions. Following a lengthy, circuitous route around the eastern and southern quadrants of his destination, he experienced a sudden loss of engine power and crashed into trees at the 4,200 foot level in mountains about 50 miles south of his destination. The pilot stated flight conditions at the time of engine power loss were light snow and about 30 degrees F ambient temperature. A subsequent engine teardown examination revealed low compression on number two cylinder due to worn piston rings and black, sooty, carbon deposits on the spark plug electrodes for cylinders number two, three, and four. Reference to the carburetor icing probability charts for the conditions present put this flight within the region labeled 'serious icing at cruise power.'
On February 4, 2000, about 1550 eastern standard time, a Mooney M20C, N5743N, registered to a private individual, operating as a Title 14 CFR Part 91 personal flight, crashed following a reported engine failure near Andrews, North Carolina. Visual meteorological conditions prevailed and an instrument flight plan was filed. The airplane received substantial damage, and the private-rated pilot, the sole occupant, sustained minor injuries. The flight departed Richmond, Virginia, for Knoxville, Tennessee, about 3 hours 50 minutes before the accident. According to the pilot, as he approached his destination, he saw that possible airframe icing conditions existed ahead, and he cancelled his instrument flight plan so that he could avoid those conditions and maneuver under VMC for a visual landing. He was near the Harris VORTAC, about 70 miles beyond, (south of) his destination at 5,500 feet msl, when he sustained a loss of engine power that necessitated a forced landing. He estimated weather conditions at the time and location of the accident to be, about 2,000 feet overcast, 3 miles visibility in snow flurries, ambient temperature 30 degrees F, and moderate turbulence. The pilot stated he had topped off his tanks with 22 gallons of 100 LL aviation fuel just before his departure, and fuel was present in the fuel tanks after the accident. According to reports by the FAA Regional Communications Center, Atlanta, at 1456, the flight was under radar control with Atlanta ARTCC, when the pilot cancelled his instrument flight plan. At 1536, the flight's radar return was seen about 6 miles north of the Harris VORTAC, (185 degrees/63 miles from his destination airport) when radio contact between N5743N and Atlanta ARTCC was lost. At 1536, a Northwest Airlines flight, acting as a radio relay for N5743N, reported that N5743N had radioed that he had passed overhead McMinn County Airport, Athens, Tennessee, (228 degrees/55 miles from destination airport). According to Air Force Rescue Coordination Center, (AFRCC) communication log sheets dated February 4, 2000, at 1705, the pilot communicated by cell phone that he is still with the downed aircraft, (at GPS coordinates N35.17 by W083.59 in a tree in Union County, North Carolina), that his aircraft radio equipment is not working, that he does not know if the ELT is going off, and that he is in need of rescue. At 1744, in response to AFRCC's query, the pilot reported he had a bump on the head and a sprained knee, and that he had only a jacket for warmth, and no survival gear. At 1710, a Georgia Emergency Management representative informed the AFRCC that ground teams are in the area of the crash, and are tracking an ELT transmission. He further reported that there is 1/2 inch of snow on the ground and it is now snowing very heavily. According to an FAA inspector, the pilot stated his flight conditions just prior to the loss of engine power at 4,500 feet included light snow, but not icing conditions, and that the engine was running perfect. He stated to the inspector that he was not using carburetor heat. Examination of the wreckage revealed the airplane came to rest supported by trees in about an 80-degree nose-down attitude at about the 4,200-foot level of forested, mountainous terrain. The airplane's nose had impacted and was resting on sloping terrain on the east face of the Unicoi Mountain Range. The entire empennage had been torn from the fuselage, and numerous indentations existed on the wing leading edges due to tree collision. The propeller blades revealed tip curling of the outer 2 inches rearward about 120 degrees, and blade leading edges revealed no gouging. Examination of the fuel tanks revealed about 12 gallons of fuel remaining in the right wing tank, and no fuel in the left wing tank. The cockpit fuel selector was found selected to the right tank. The throttle was found full open, the propeller full increase rpm, and the mixture full rich. The carburetor heat was in the full in or "off" position. The transponder code read "2177" and the function switch was off. The altimeter read 4,900 feet. The engine was removed and subjected to disassembly examination, with FAA oversight, at the salvager's hangar. Internal examination of the number two cylinder revealed excessively worn piston rings and excessive carbon buildup in the cylinder and on the piston. No other mechanical irregularities were noted in the ignition, lubrication, fuel, induction, or exhaust systems. All cockpit controls to the engine were functional. The number two, three, and four spark plugs were fouled with black, sooty carbon deposits. According to a telephone conversation between the pilot and an NTSB investigator on June 30, 2000, as a follow-up to his submission of NTSB form 6120 1/2, he stated, (1) he selected carburetor heat before he experienced any engine instability symptoms, and it was selected on at the time of the loss of engine power, (2) the ceiling at the crash site at the time of the accident was about 2,000 feet agl, (3) the in-flight turbulence experienced by the pilot just before the accident was moderate vs. his previously reported severe, (4) the airport he transmitted having passed over and was overheard by a Northwest Airlines flight who subsequently relayed to ATC could have been Andrews-Murphy Airport, Andrews, North Carolina, instead of the McMinn County Airport, Athens, Tennessee, (5) the pilot and aircraft log books were lost in the crash, probably due to theft. The fueler at the departure airport confirmed that 22 gallons of 100LL fuel was pumped aboard N5743N at 1155 on February 4, 2000, and represented a full top off. A fuel contamination check was conducted on the fuel tanker sumps and filter sumps for the truck used for N5743N's fuelling. The recorded readings were, "clean of solids and bright in color". Reference to carburetor icing charts reveals that an ambient temperature of 30 degrees F, and a dew point temperature of 25 degrees F, as reported by the Knoxville FSS and the pilot, for the time of the accident, would put the flight's probability within the region labeled, "serious icing at cruise power". A copy of the chart is included in this report.
The pilot's failure to use carburetor heat in a timely manner while maneuvering in conditions conducive to carburetor icing, resulting in the loss of engine power and collision with trees during the subsequent emergency descent.
Source: NTSB Aviation Accident Database
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