CEN12FA196
CEN12FA196

HISTORY OF FLIGHT

On March 21, 2012, at 1112 central daylight time, a Beech 35, N3871N, was substantially damaged when it impacted an open field under unknown circumstances five miles north of Glencoe, Minnesota. A post impact fire ensued. The non-instrument rated private pilot and two passengers were fatally injured. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Instrument meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from Crystal Airport (KMIC), Minneapolis, Minnesota, and was en route to Craig, Colorado.

Several witnesses in the area reported hearing an airplane flying low and hearing a loud snap or pop. One witness heard a second explosion as the airplane struck the ground. These witnesses described the weather as low overcast skies with limited visibility due to light fog and mist. There was no radar data available from the Federal Aviation Administration for the accident flight.

PERSONNEL INFORMATION

The pilot, age 52, held a private pilot certificate with a single engine land rating. He was issued a third class airman medical certificate on October 28, 2011. The certificate contained the limitation “must wear corrective lenses.” At the time of application for his airman medical certificate, the pilot reported a total time of 250 hours, and no flight time within the preceding six months.

The pilot’s family provided the National Transportation Safety Board (NTSB) Investigator-in-Charge two logbooks for review. A third logbook, the pilot’s training logbook was not requested and was retained by the family; 57.5 hours of flight instruction and 41.1 hours of solo flight time were recorded in this logbook. The first logbook covered the time between June 23, 2005, and June 13, 2009. During this time, the pilot logged 117 hours in an Alon A-2A. There were no endorsements recorded in this logbook and no instrument flight hours logged.

The second logbook covered the time between November 10, 2011, and March 11, 2012. During this time, the pilot logged 32.6 hours of flight time, 24.2 of which were logged in the accident airplane. On November 12, 2011, the pilot completed the requirements of a flight review and received a pilot-in-command endorsement for the operations of complex aircraft. The two logbooks did not reflect any instrument training or instrument experience. The pilot did not have an endorsement for operating high performance aircraft.

AIRCRAFT INFORMATION

The accident airplane, a Beech 35 (serial number D1113), was manufactured in 1947. It was registered with the Federal Aviation Administration (FAA) on a standard airworthiness certificate for normal operations. A Continental Motors E-185-11 engine rated at 205 horsepower at 2,600 rpm powered the airplane. The engine was equipped with a two-blade, propeller. According to the previous owner, the airplane was not certified, nor was it maintained for flight into instrument meteorological conditions.

The airplane was maintained under an annual inspection program. A review of the maintenance records indicated that an annual inspection had been completed on March 22, 2011, at an airframe total time of 4,744.0 hours, and a tachometer time of 595.7.

METEOROLOGICAL INFORMATION

Surface observations from Glencoe Municipal Airport (KGYL) in Glencoe, Minnesota, which was located approximately 5 miles south-southeast of the accident site, indicated instrument flight rule (IFR) conditions prevailed at KGYL at the time of the accident. At 1116, a KGYL automated observation reported: wind from 200 degrees at 7 knots, visibility of 5 miles, mist, ceiling overcast at 900 feet above ground level, temperature 14 degrees Celsius (C) and dew point temperature 13 degrees C, altimeter setting 29.98 inches of mercury, Remarks: station with a precipitation discriminator, hourly temperature 14.1 degrees C and hourly dew point temperature 12.7 degrees C.

METAR KGYL 211515Z AUTO 20007KT 5SM BR OVC009 14/13 A2998 RMK AO2 T01400127
METAR KGYL 211536Z AUTO 20008KT 5SM BR BKN007 OVC019 14/13 A2998 RMK AO2 T01400127
METAR KGYL 211556Z AUTO 19007KT 4SM BR BKN007 OVC016 14/13 A2998 RMK AO2 T01420130
METAR KGYL 211616Z AUTO 20007KT 5SM BR OVC009 14/13 A2998 RMK AO2 T01410127
METAR KGYL 211636Z AUTO 22006KT 5SM BR OVC007 14/13 A2998 RMK AO2 T01420126

Imagery retrieved from the WSR-88d weather radar near Minneapolis, Minnesota (KMPX), indicated the area of the accident site would not have been affected by phenomena associated with convective weather.

Wind data below 3,000 feet retrieved from commercial aircraft arriving and departing Minneapolis-St. Paul International/Wold-Chamberlain Airport (KMSP) near the accident time identified relatively light wind magnitudes (< 10 knots). Data from these aircraft identified the freezing level to be between 9,500 and 10,000 feet.

There were no publically disseminated pilot reports made within two hours of the accident time in Minnesota. An Airman’s Meteorological Information (AIRMET) advisory for IFR conditions was active for the accident location at the accident time. An AIRMET advisory for moderate icing between the freezing level and flight level 180 was active for the accident location at the accident time. No AIRMETs for turbulence were active below flight level 180 for the accident location at the accident time. No SIGMETs were active for the accident location at the accident time.

The Area Forecast active for the accident time forecasted: for southwest Minnesota – ceiling overcast at 2,500 feet mean sea level (msl) with occasional visibility of 3 to 5 miles, light rain and mist; for southeast Minnesota – scattered clouds at 3,000 feet msl, broken ceiling at 5,000 feet msl, widely scattered light rain showers, with ceiling lowering to between 3,000 and 3,500 feet msl after 0700.

The pilot contacted the Direct User Access Terminal System (DUATS) on March 21, 2012, at 0536 universal time coordinate and requested temporary flight restriction information for the continuous United States. The pilot did not request weather information for his route of flight, nor did he file a flight plan. Investigators were unable to locate any evidence that the pilot obtained a weather briefing through recorded services.

WRECKAGE AND IMPACT INFORMATION

The wreckage was scattered over 900 feet between two plowed fields divided by a field service road. The northern field was a dormant cornfield and the southern field was a dormant soybean field. Small red paint chips were scattered throughout the entire debris field and along the flight path described by the ground witness. The debris field was oriented from west to east, with the energy vector on a measured heading of 108 degrees.

The western most portion of the debris field initiated with a portion of the leading edge skin from the left wing. The sheet metal was 70 inches long and was torn and wrinkled. Several additional pieces of torn sheet metal and ribs from the left wing were located 15 feet to the east of this portion of the left wing.

A second piece of sheet metal from the left wing was located to the east of the start of the debris field. The pitot tube remained attached on the bottom portion of the skin and was impacted with mud. Plexiglas, the landing light lens, navigation antennae, paint chips, the lower spar cap, and small pieces of torn sheet metal were all located within the initial portion of the debris field.

The left aileron and a portion of left wing skin were found next in the debris field. The piece was 80 inches long, and was torn and buckled. The bell crank separated from this portion of the left wing assembly. A small portion of the aft wing spar remained attached.

The left flap and a portion of left wing skin were next in the debris field. The piece was 87 inches long and included a portion of the rear left wing spar cap. The left flap actuator was attached to the separated left wing aft spar and the left flap attachment. The left flap actuator extension was measured and found to be approximately 2 and 1/16 inches, which corresponds to a 2 degree flap position.

An inboard leading edge portion of the left wing root, to include the fuel tank bladder was 47 inches long. The fuel bladder was torn and no residual fuel was present in the tank.
The empennage was located on the service road between the north and south fields. The empennage included the ruddervator, the stabilator, and the aft portion of the fuselage. The right leading edge was unremarkable. The left leading edge was crushed and dented. The skin on the fuselage, adjacent to the left leading edge attach-point, contained black marks. The ruddervator remained attached to the stabilator. The elevator trim actuator extension was measured and found to be 13/16 inch, which corresponds to a 10 degrees trim tab trailing edge down. The bottom portion of the empennage skin was crushed up and broken.

Both ruddervator counter weights were located in the north field, east of the empennage.
The left main landing gear assembly included the wheel, tire, brake assembly, and gear door cover. The assembly was impact damaged and embedded with mud but was otherwise unremarkable.

The first extensive ground scar initiated in the southern field, just south of the service road. The scar was 8 feet long and 8 inches at its widest point. The scar was shallow in depth and the ruts of the field prevented an accurate measurement of depth.

The second ground scar started 17 feet southeast of the end of the first ground scar. The second ground scar had two larger craters with dirt displaced towards the southeast. The scar was 18 feet in length, 10 feet 6 inches at its widest point, and approximately 12 inches at the deepest point. There was a strong smell of aviation fuel within the dirt of the crater. The second scar contained structure from the wing, fragmented fuselage skin, and wood from the cabin flooring.

The differential mechanism assembly for the elevator and rudder control was located within the debris field and remained entangled with a piece of fuselage skin. The left and right rudder cables were intact. Both cables were attached to their respective bellcrank mechanism and both were separated from the forward bellcrank. The rudder balance cables were intact. One end of the cable was attached to the left rudder differential mechanism while the other end was separated from the right rudder differential mechanism. The UP elevator cable was attached to the differential mechanism. The UP elevator cable was separated with signatures consistent with tension overload. The DOWN elevator cable (small cable), between the differential mechanism and the reduction bellcrank, was attached to the differential mechanism, but was separated from the reduction bellcrank. The DOWN elevator cable (long cable) was attached to the separated reduction bellcrank and the other end of the cable was separated with signatures consistent with tension overload. The elevator trim cables were intact and attached to the trim tab bellcrank and to each trim control surface.

The main wreckage was located 80 feet southeast from the end of the last ground scar. The main wreckage included the right wing assembly and forward fuselage.

The right wing included the right flap, right aileron, the right main landing gear assembly, and part of the main carry through structure. The right wing came to rest inverted and was separated from the fuselage. The bottom portion of the right wing exhibited thermal damage. The fuel tank was compromised and exhibited exposure to heat and fire. There was no residual fuel. The inboard leading edge was crushed at the landing light. The landing gear actuator was in a position consistent with the landing gear being retracted or up. The rear main carry through spar separated at midspan and remained attached to the right wing. Aileron continuity was confirmed from the aileron quadrant located at the center section of the fuselage to the right aileron and to the left aileron outboard bellcrank assembly. The left aileron push/pull tube was separated. Each of the separated ends was attached to the left aileron bellcrank and the left aileron. The aileron quadrant located at the center section of the fuselage was separated. Continuity from the quadrant to the cockpit was confirmed with cable separations consistent with tension overload. The right flap actuator was attached to the right wing aft spar and the flap attachment. The flap actuator extension was measured and found to be 1 and 3/4 inches, which corresponds to 0 degrees - a flap up position.

The engine separated from the airframe and came to rest 20 feet to the south of the main wreckage. The engine contained the propeller, propeller flange, and engine accessories. Blade A was bent aft and twisted. Blade B was relatively straight and exhibited slight twisting, leading edge polishing, and chord wise scratches. Both magnetos remained attached to the engine. The leads were mangled during the impact. Both magnetos were removed from the engine and rotated by hand; both produced a spark at each lead. Valve covers were removed on both sides. The cylinder 2/4/6 side of the engine sustained impact damage and the rocker arms and valve train area was embedded with mud. The top bank of spark plugs was removed revealing normal operating signatures as compared to the Champion Aviation Check-A-Plug chart. A boroscope of the engine cylinders revealed no anomalies. The engine was rotated through by hand and power train continuity was confirmed. Thumb compression was noted on all cylinders except the number four cylinder. The intake valve on the number four cylinder would not close fully due to impact damage. The vacuum pump rotated, by hand, without hesitation or binding. Air movement was noted during the rotation.

A portion of the forward fuselage was adjacent and east of the right wing. The forward portion of the fuselage included the forward cabin structure, and the instrument panel. The instrument panel and cabin structure was charred, melted, and partially consumed by fire.
The cabin door and fragmented pieces of the fuselage were scattered to the east of the main wreckage. The fuselage structure exhibited exposure to heat and fire. Only the frame of the cabin seats remained and the skin and seats where charred, melted, and partially consumed by fire.

The top forward fuselage skin, antenna assembly, and battery were the farthest east components in the debris field and were located 15 feet east of the cargo door.

MEDICAL AND PATHOLOGICAL INFORMATION

The Midwest Medical Examiner’s Office performed the autopsy on the pilot on March 22, 2012. The autopsy concluded that the cause of death was multiple blunt force injuries and the report listed the specific injuries.

The FAA’s Civil Aerospace Medical Institute (CAMI), Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy (CAMI Reference #201200056002). Tests for carbon monoxide and cyanide were not performed. Results were negative for volatiles and drugs.

TESTS AND RESEARCH

The wreckage was recovered and relocated to a hangar in Minneapolis, Minnesota.

The left wing was laid out on the hangar floor in the correct anatomical position to understand damage, fragmentation, and impact angles. When laid out, the left wing exhibited bending in an upward direction. The left wing was fragmented into several smaller pieces. The leading edge of the left wing separated into two main sections. The first section extended from the wing root out board to the landing light. The tops skin on this section near the wing root exhibited an upward compression bend. The outboard section was crushed and wrinkled. The forward upper and lower spar caps separated from the wing spar. Both spar caps were twisted and bent. The lower spar cap was partially separated at midspan.

The flap assembly remained attached to the separated wing section. The flap actuator remained attached to the flap and the wing structure. The outboard separation point was at the junction of the wing flap and aileron. The flap exhibited aft diagonal buckling, at midspan, in an upward direction.

The aileron remained attached to the separated wing section. The wing skin and aileron were bent approximately 45 degrees at the outward hinge point. The aileron push pull rod was separated; one end remained attached to the aileron and the other end was attached to the separated bell crank. The aileron and wing skin exhibited extensive red paint transfer and scratching. The aileron exhibited paint transfer scratches consistent in spacing with rivets.
The forward carry through spar had been modified by supplemental type certificate SA 222 – CE. The carry through spar separated partially approximately midspan. The second point of separation was outboard towards the left wing root. The second point of separation exhibited upward bending and forward to aft twisting. The corresponding mating surface was impact damaged and fragmented. The rear carry through spar was broken into several smaller pieces.

The forward upper and lower carry-through spar were secured and sent to the NTSB Materials Laboratory in Washington, DC, for further examination. The fracture surfaces on the components were cleaned and visually examined. All fracture surfaces exhibited slant fractures consistent with overstress failure.

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