Beechcraft 35 B33 N8910M

Summary

On 24 September 2013 at about 13:20 local time, a Beechcraft 35 B33 registered N8910M, operated by Rex A Ott, was involved in an accident near Urbana, Indiana, United States. 3 people were on board and one was seriously injured, one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

24 September 2013 at 13:20

Classification

Accident

Location

Urbana, Indiana, United States

Coordinates

40.8783, -85.7781

Aircraft

Beechcraft 35 B33

Registration

N8910M

Category

Airplane

Year built

1963

Engines

1

Operator

Rex A Ott

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Washington → Van Wert

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN13LA557

1 person was seriously injured.

The failure of the crankshaft following several overheating events that had led to a stress crack and the subsequent fracture forward of the No. 6 rod journal.

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

Read the full NTSB narrative

The pilot reported that, while in cruise flight, he noticed a change in the engine sound and a 100-rpm increase on the tachometer. He adjusted the propeller control to lower the rpm, but the rpm immediately increased to over 3,500, which is above the red line. The pilot reduced the propeller and throttle controls, but the propeller continued to overspeed. The propeller then separated from the airplane, and engine oil covered the windscreen. The pilot subsequently made a forced landing to a soft bean field, which resulted in substantial damage to the fuselage, wings, and engine mounts. A postaccident examination of the engine revealed that the crankshaft was fractured forward of the No. 6 rod journal across the oil transfer collar area and that the No. 6 rod had separated from the crankshaft. An examination of the fracture revealed evidence of several overheating events at the surface of the crankshaft next to the oil transfer collar hole. A crack had formed adjacent to the overheated surface, and the surface crack led to a stress crack, which formed the surface of the main separation fracture.

Quoted verbatim from the NTSB record.