Bell 206B N385EH

Summary

On 9 September 1990 at about 22:00 local time, a Bell 206B registered N385EH, operated by ERA Aviation Inc., was involved in an accident near Kokhanok, Alaska, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

9 September 1990 at 22:00

Classification

Accident

Location

Kokhanok, Alaska, United States

Coordinates

59.8493, -154.5598

Aircraft

Bell 206B

Registration

N385EH

Category

Helicopter

Engines

1

Operator

ERA Aviation Inc.

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC90LA170

1 person was seriously injured.

THE FAILURE OF THE COMPRESSOR END OF THE AIR COMPRESSOR SCROLL TO TEE TUBE ASSEMBLY CAUSING THE ENGINE TO SPOOL DOWN. THE FORCED LANDING IN ENEVEN, UNPREPARED, AND LIGHTLY FORESTED TERRAIN WERE FACTORS.

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

Read the full NTSB narrative

THE PILOT EXPERIENCED A SPOOL DOWN ON THE TURBINE ENGINE. EXAMINATION OF THE ENGINE REVEALED THAT THE AIR COMPRESSOR SCROLL TO TEE TUBE ASSEMBLY COMPRESSOR END FITTING HAD BROKEN. METALLURGICAL EXAMINATION OF THE PART SHOWED THAT THERE WERE NO MATERIAL IRREGULARITIES, THAT THE TUBE BEND DEVELOPMENT AND LINEAR MEASUREMENTS VARIED FROM THE ENGINEERING DRAWINGS, AND THAT THE TUBE ASSEMBLY FAILED IN A FATIGUE MODE. THE ORIGIN WAS ON THE TUBE O.D. APPROXIMATELY 0.020 INCH BELOW THE 'B' END FLARE RADIUS.

Quoted verbatim from the NTSB record.