Bell 212 N873HL

Summary

On 4 September 2006 at about 22:50 local time, a Bell 212 registered N873HL, operated by Department of Agriculture, U.S. Forest Service, was involved in an accident near Happy Camp, California, 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

4 September 2006 at 22:50

Classification

Accident

Location

Happy Camp, California, United States

Nearest airport

Happy Camp (36S)

Coordinates

41.7906, -123.3889

Aircraft

Bell 212

Registration

N873HL

Category

Helicopter

Engines

2

Operator

Department of Agriculture, U.S. Forest Service

Operating rule

Public Use

Purpose of flight

External Load

Phase of flight

Not recorded

Route

Happy Camp → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX06TA284

Nobody was injured.

Failure of compressor second stage stator vane for undetermined reasons while maneuvering.

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

Read the full NTSB narrative

An engine fire warning light illuminated in the cockpit and the pilot observed smoke coming from the helicopter. He pulled the fire extinguisher handle on the number 2 engine and made a rapid descent to the airport. The pilot dropped the long line and landed without further incident. A post-landing examination of the helicopter revealed that the external surfaces of the Number 2 engine were covered in soot. A hole, which appeared to originate inside the engine, was observed on the gas generator case at the 5 o'clock position (aft looking forward). Post accident disassembly and inspection was performed on the number 2 engine. During the teardown, investigators found foreign debris, consistent in appearance to a stator vane, lodged in a diffuser pipe. The diffuser pipe, which directs compressor discharge air to the combustion area, was located at approximately the 5 o'clock position (aft looking forward). Further inspection revealed a fractured stator vane in the compressor second stage stator assembly. Due to impact and heat damage to the stator vane fracture surface, the cause of cracking could not be determined. Pratt & Whitney Canada investigators, in the presence of Federal Aviation Administration inspectors, concluded the following. "The perforation of the gas generator case was most likely caused by a disturbance of compressed air flow from the diffuser pipes. The restriction in airflow caused by the lodged stator vane limited the flow of combustion liner cooling air, resulting in a localized increase in temperature and subsequent burning through the combustion liner and the gas generator case." The engine teardown and inspection revealed no other significant anomalies.

Quoted verbatim from the NTSB record.