Beechcraft 36 N7472N

Summary

On 18 December 2008 at about 08:55 local time, a Beechcraft 36 registered N7472N was involved in an accident near Louisville, Kentucky, United States. One person was on board and one died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 December 2008 at 08:55

Classification

Accident

Location

Louisville, Kentucky, United States

Coordinates

38.2886, -85.5611

Aircraft

Beechcraft 36

Registration

N7472N

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Chicago → Louisville

Aircraft damage

Substantial

Weather

IMC

Light

Night

NTSB number

ERA09FA093

1 person died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.