Pilot Debrief

BEECH 36 near Louisville, KY — 2008-12-18

Final reportERA09FA093
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Date
2008-12-18
Location
Louisville, KY, USA
Aircraft
BEECH 36
Registration
N7472N
Category
Airplane
Highest injury
Fatal
Fatalities
1

Probable cause

The pilot’s continued operation of the aircraft with known deficiencies. Contributing to this accident was the improper sealing of the engine case during overhaul.

Contributing factors

Contributing to this accident was the improper sealing of the engine case during overhaul.

NTSB narrative

The pilot was cleared for the Area Navigation (RNAV) Global Positioning System (GPS) approach for runway 24 at his destine airport. The weather at the airport was reported as visibility, 6 statute miles; mist, overcast clouds at 800 feet. When the airplane was about 9 miles from the airport, the pilot reported an emergency; advising of an “engine failure”. A witness on the ground observed the airplane flying low over the golfing community. The witness reported the weather was cold, with little wind, cloudy, and misty at the time, and the street lights and a car dealership across the highway were the only illumination for the area that dark morning. The airplane was on an approximate course of 340 degrees and about a height of 30 feet above ground level (agl) when the right wing made contact with a tree at the beginning of the fairway, which was located between a row of residential homes and a row of tall trees. The right wing and the gear separated at the wheel well inboard section, the airplane contacted the ground inverted and came to rest 175 feet down the fairway from the initial contact point. Examination of the engine revealed the crankshaft and counterweight assembly was fractured through at the forward fillet radius of the number 2 main bearing journal. The number 2 main bearing journal exhibited scoring consistent with bearing rotation. The number 2 main bearings’ fragments were located in the oil sump. The number 3 main bearing journal was fractured at the rear fillet area. Examination of the crankcase halves, revealed the presence of silk thread patterns and gasket making material on the sealing surfaces of the main bearing bosses, which is not part of the engine’s manufacturer maintenance instructions that resulted in improper torque valves obtained during the crankcase halves assembly. The number 2 main bearing boss was severely damaged on both the left and right case halves. The damage included rotational mechanical gouging and deformation of the boss area behind the bearing, including mushrooming deformation of the boss. The engine was overhauled 58 hour before the accident. Witnesses reported the pilot mentioned having oil pressure problems with the overhaul engine prior to the accident.

NTSB coding

Evidence available

  • ATC audio
  • Photos
  • 19 docket documents
View NTSB final reportView NTSB docket

Docket documents19

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