Bell 206 N206JH

Summary

On 26 April 2019 at about 14:00 local time, a Bell 206 registered N206JH, operated by Wilbur Ellis Co, was involved in an accident near Oakridge, Oregon, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

26 April 2019 at 14:00

Classification

Accident

Location

Oakridge, Oregon, United States

Coordinates

43.5539, -122.4758

Aircraft

Bell 206

Registration

N206JH

Category

Helicopter

Year built

1980

Engines

1

Operator

Wilbur Ellis Co

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Oakridge → Oakridge

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR19LA122

Nobody was injured.

A total loss of engine power following the failure of a 3rd stage turbine blade due to low- and high-cycle fatigue.

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

Read the full NTSB narrative

During the agricultural aerial application flight, the helicopter lost engine power, and the pilot performed an autorotation into sloping, tree-covered terrain. Examination of the engine revealed that a blade from the 3rd stage turbine wheel had been liberated, resulting in the loss of engine power. The blade’s fracture surface indicated that it was initiated in a low-cycle fatigue mode near the trailing edge radius of the blade and progressed to a high-cycle fatigue process along the blade chord, which finally resulted in overload failure. The initiation event for the failure could not be determined; however, it was likely caused by operation within an engine speed avoidance range, an engine speed/airframe interaction of unknown origin, inadequate engine temperature management on startup, inadequate wheel design or undetermined manufacturing defect, or combinations thereof. The blade had not been operated beyond its overhaul or inspection time limit. Similar blade failure was associated with five previous accidents and two previous incidents. An in-service replacement program was started by the engine manufacturer on July 30, 2021, requiring removal and replacement of the 3rd stage turbine wheel with a new design at the next scheduled replacement time.

Quoted verbatim from the NTSB record.