Aviation Accident Summaries

Aviation Accident Summary CEN12FA517

Imperial, NE, USA

Aircraft #1

N36286

BELLANCA 7GCBC

Analysis

The airplane impacted rising terrain while traveling in a generally eastward direction. Postaccident examination of the airplane and its systems did not reveal any anomalies consistent with a preimpact failure or malfunction. At the time of the accident, the airplane was travelling east into the rising sun. The sun’s position was about 14 degrees above the horizon and 80 degrees east of north. It is likely that the pilot was blinded by the sun during this portion of the flight and did not see the rising terrain.

Factual Information

HISTORY OF FLIGHT On August 4, 2012, about 0713 mountain daylight time, a Bellanca 7GCBC, N36286, sustained substantial damage when it impacted rising terrain while maneuvering near Imperial, Nebraska. The pilot was fatally injured. The aircraft was registered to German Land and Cattle and operated by the pilot as a business flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight originated from the Imperial Municipal Airport (IML), about 30 minutes before the accident. The pilot reportedly used the airplane for various uses including checking livestock water tanks and herding cattle. A family member that was interviewed at the accident site was not sure what the purpose of the accident flight was, but commented that there were no cattle or water tanks in the immediate area of the accident. He speculated that the pilot may have been flying back to IML when the accident occurred. The initial impact point was located on the west side of a ridge about 3.5 miles south of Imperial, Nebraska. The general direction of travel at the time of the initial impact was to the east. The terrain in the area consisted of rolling hills with the tops varying in elevation. Some of the ridges rose above the valleys below by an estimated 100 to 150 feet. The hill that was impacted was one of the tallest in the immediate area of the accident. The initial impact point was about 10 feet below the top of the ridge in the direction of the airplane’s travel. To the south, the ridge continued to rise. To the north the ridge descended to a valley below. After the impact with the hill, the airplane traveled over the ridge to the east and into a valley on the east side of the ridge. It came to rest pointed in a predominately north direction. The initial impact point included two ground scars spaced approximately the same distance apart as the airplane’s main landing gear spread. Another ground scar was centered between the 2 landing gear scars and continued from this point in an eastward direction for about 10 feet. This scar was consistent with the impact of the fuselage. A fourth scar was found to the south and east of the landing gear scars. This scar was consistent with right wing impact. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with single-engine land, multiengine land, and instrument airplane ratings. He was issued a second-class airman medical certificate, with a restriction for corrective lenses, on April 3, 2012. The pilot ‘s flight logbook was not recovered during the investigation, however, the pilot reported having 280 hours total flight experience and 10 hours in last six months as of exam dated April 3, 2012. AIRCRAFT INFORMATION The accident airplane was a Bellanca 7GCBC Citabria, serial number 562-73. It was a two-place, strut-braced high-wing, single engine airplane, with a conventional (tailwheel) landing gear configuration. The airplane was powered by a 150-horsepower Lycoming O-320 four-cylinder, reciprocating engine. The aircraft maintenance records were not recovered during the investigation. METEOROLOGICAL INFORMATION Weather conditions recorded by the IML Automated Surface Observing System (ASOS), located about 3.5 miles north of the accident site, at 0653, were: wind from 350 degrees at 8 knots, visibility 10 miles, clear sky, temperature 16 degrees Celsius, dew point 10 degrees Celsius, and altimeter 30.11 inches of mercury. At the time of the accident the sun was about 14 degrees above horizontal and 80 degrees east of north. WRECKAGE AND IMPACT INFORMATION The initial impact point was located on the west side of a ridge about 3.5 miles south of the town of Imperial, Nebraska. The general terrain in the area consisted of rolling hills with the tops varying in elevation. Some of the ridges rose above the valleys below by an estimated 100 to 150 feet. The hill that was impacted was one of the tallest in the immediate area of the accident. The initial impact point was about 10 feet below the top of the ridge in the direction of the airplane’s travel. To the south, the ridge continued to rise. To the north the ridge descended to a valley below. Impact evidence was consistent with the airplane impacting the hill and then travelling over the ridge to the east and into a valley on the east side of the ridge. It came to rest pointed in a predominately north direction. The initial impact point included two ground scars spaced approximately the same distance apart as the airplane’s main landing gear spread. Another ground scar was centered between the two landing gear scars and continued from this point in an eastward direction for about 10 feet. This scar was consistent with the impact of the fuselage. A fourth scar was found to the south and east of the landing gear scars. This scar was consistent with right wing impact. Both main landing gear separated from the fuselage and were located between the initial impact point and the main wreckage. Also located between the initial impact point and main wreckage were numerous pieces of clear acrylic plastic, shards of painted plastic the same colors as the airplane and metal pieces identified as various aircraft components. The main wreckage included all major portions of the airframe including the fuselage, tail surfaces, both wings and the engine. The engine was partially separated and twisted from its normal mounting location on the fuselage. The propeller was separated from the engine. The forward fuselage was crushed rearward and the aft fuselage was bent toward the right approximately at the position of the rear seat. All of the airplane’s tail surfaces remained attached with all hinge locations intact. Both wings remained partially attached to the fuselage with fire damage to the inboard portions of the spars. The wing struts remained attached to the fuselage and wing spars but exhibited buckling along their length. The left aileron remained attached to the wing and all of the hinges were intact. The left flap remained attached to the wing and all hinges were intact, except the moveable inboard hinge section was separated from the flap which was bent downward about 90 degrees. The right aileron remained attached to the wing and all hinge locations were intact. The rear spar was broken in two pieces between the center and outboard aileron hinge locations. The right flap remained attached and all hinges were intact. No evidence of a preimpact structural failure was observed. The rudder control system was completely intact except that a tab welded to the right front rudder pedal for cable attachment had been torn loose from the pedal. The aileron control system was completely intact with the exception of the cast aluminum bellcrank mounted to the aft end of the control stick torque tube. The bellcrank was separated at the tube and a portion remained within the tube. In addition, the arms of the bellcrank attached to the cables were both separated from the remainder of the bellcrank casting. There was melting of the metal on the fracture surface faces. The “up” elevator cable remained attached at both ends. The “down” elevator cable remained attached at the elevator and to a portion of the cast aluminum control stick socket. The portion attached to the elevator cable had separated from the remainder of the socket assembly. The flap cable remained attached at both flap locations and at the flap handle within the cockpit. Engine examination – The engine came to rest with the crankshaft pointing up. The engine was removed from the wreckage and supported from its lifting eye. The firewall was removed to allow access to the rear of the engine. The upper set of spark plugs were removed and examined and exhibited a grayish black appearance. The plugs from the aft two cylinders had wet oil on them due to the resting position of the engine. Oil was observed leaking from the engine. With the spark plugs removed, the engine rotated smoothly and the impulse coupling on the magneto could be heard clicking. The rocker covers were removed and valve action was confirmed on all valves by rotation of the engine. Compression and suction were verified on all cylinders. Each of the 8 spark plug wires were cut approximately 3 inches long and spark was observed from the center conductor to the braided sheath when the engine was rotated by hand. The carburetor flange remained attached to the engine. It was fractured through the butterfly valve shaft hole. The butterfly shaft was broken on the side that had the throttle control arm. The float chamber was opened and appeared clean. The mixture control shaft rotated freely. The floats were a black solid plastic/foam type material as opposed to hollow brass floats. The float valve moved freely within its seat. The propeller had separated from the engine. Examination of the propeller blades revealed leading edge polishing, and chordwise scratching of both blades. One blade had a chordwise gouge on the uncambered side. The other blade was bent rearward about 90 degree at mid-span. The propeller extension holes that engage the crankshaft dowels exhibited slight elongation in a direction tangential to the bolt circle consistent with engine torque at the time of separation Postaccident examination did not reveal any anomalies consistent with a preimpact failure or malfunction. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was performed by the Regional West Medical Center, Scottsbluff, Nebraska, on August 6, 2012. The pilot's death was attributed to injuries received in the accident. Toxicology testing was performed by the FAA Civil Aerospace Medical Institute. Testing results were negative for all substances in the screening profile.

Probable Cause and Findings

The pilot’s failure to maintain adequate clearance from rising terrain while flying toward the rising sun, which interfered with his ability to see the terrain.

 

Source: NTSB Aviation Accident Database

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