Bell 47G-4A N124SH

Summary

On 24 July 2010 at about 19:00 local time, a Bell 47G-4A registered N124SH, operated by Scotts Helicopter Services Inc, was involved in an accident near Rochester, Minnesota, 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

24 July 2010 at 19:00

Classification

Accident

Location

Rochester, Minnesota, United States

Coordinates

44.0497, -92.3264

Aircraft

Bell 47G-4A

Registration

N124SH

Category

Helicopter

Year built

1967

Engines

1

Operator

Scotts Helicopter Services Inc

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Local Airstrip → Local Airstrip

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN10LA431

1 person died.

The total loss of engine power due to a high-cycle fatigue fracture of a first-stage compressor blade. The reason for the fracture could not be determined during postaccident examination.

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

Read the full NTSB narrative

A witness reported that the agricultural helicopter was refueled and that the hopper was loaded with chemical before departure. He reported that he saw the helicopter depart, that the engine sounded normal, and that the helicopter's departure and flightpath appeared normal. He then saw a "brown puff of smoke" come from the helicopter, and it subsequently descended and impacted a hill. A postaccident engine examination revealed that the compressor rotor assembly had failed. The metallurgical examination of the compressor rotor assembly revealed that a single first-stage compressor blade had fractured in high-cycle fatigue. The microstructure, hardness, and chemistry of the first-stage compressor wheel conformed to the requirements of the engineering drawing. No evidence of corrosion was found near the fracture origin. The engine was installed on the helicopter during the last annual maintenance inspection conducted 3 days before the accident. Evidence indicated that the engine was installed properly. The reason for the fracture could not be determined.

Quoted verbatim from the NTSB record.