Beechcraft E50 N4265R

Summary

On 28 June 1997 at about 19:30 local time, a Beechcraft E50 registered N4265R, operated by Tennessee Skydiving Center, was involved in an accident near Tullahoma, Tennessee, United States. 9 people were on board and 2 were seriously injured, 7 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

28 June 1997 at 19:30

Classification

Accident

Location

Tullahoma, Tennessee, United States

Nearest airport

Tullahoma Regional (THA)

Coordinates

35.3703, -86.2010

Aircraft

Beechcraft E50

Registration

N4265R

Category

Airplane

Engines

2

Operator

Tennessee Skydiving Center

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ATL97LA091

2 people were seriously injured.

improper operation of the engine that produced internal damage, and improper servicing of the airplane by the owner/pilot mechanic that resulted in the subsequent mechanical failure of the engine crankshaft counterweight. Contributing to the accident was the pilot's inability to feather the propeller.

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

Read the full NTSB narrative

The airplane was being used for sport parachute operations. During the initial climb after takeoff the right engine failed followed by the airplane's slow descending right turn into wooded terrain. The airplane crashed through trees and caught on fire. The fire was extinguished prior to the destruction of the airplane. Subsequent examination of the engine revealed that one crankshaft counterweight had broken its retaining lugs and was liberated inside the engine, resulting in sudden stoppage of the engine. The sudden stoppage prevented the pilot from feathering the propeller. Metallurgical examination of the crankshaft and counterweight revealed damage that was consistent with 'detuning' of the engine counterweights. Counterweight detuning results from excessively rapid throttle movements. Additionally, the engine log indicated that during an oil change 8 days before the accident, wear metal was found in the oil. The airplane continued to be flown with no further maintenance action taken.

Quoted verbatim from the NTSB record.