Eurocopter EC 130 B4 N151GC

Summary

On 27 June 2017 at about 21:03 local time, a Eurocopter EC 130 B4 registered N151GC, operated by Papillon Grand Canyon Helicopters, was involved in an accident near Boulder City, Nevada, United States. 7 people were on board and 2 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

27 June 2017 at 21:03

Classification

Accident

Location

Boulder City, Nevada, United States

Coordinates

35.9675, -114.8922

Aircraft

Eurocopter EC 130 B4

Registration

N151GC

Category

Helicopter

Year built

2007

Operator

Papillon Grand Canyon Helicopters

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Boulder City → Boulder City

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR17LA133

2 people had minor injuries.

A loss of engine power due to the failure of the manufacturer to reinstall the oil filter after it was removed for inspection, which led to coke pollution that obstructed the oil jet and resulted in the subsequent oil starvation of the axial compressor rear bearing oil and its subsequent failure.

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

Read the full NTSB narrative

The commercial pilot reported that, during an air tour flight, the engine lost total power. He initiated an autorotation to a nearby helicopter pad, during which the helicopter contacted power lines. He subsequently conducted an emergency landing on up-sloping terrain. Postaccident on-site engine examination revealed that both the gas generator and power turbine were seized and could not be rotated by hand and that there was a significant amount of heat damage to the turbine blades and thermocouples. The vehicle and engine multifunction display recorded multiple engine temperature exceedances during the accident flight. Metal particles were found on the accessory gearbox magnetic plug. Further, no oil filter was found installed in the airplane. Subsequent engine examination revealed that there was a hole in the centrifugal compressor. Examination further revealed that the No. 2 oil jet for the axial compressor rear bearing was obstructed, which resulted in oil starvation of the bearing and its subsequent failure. The bearing failure subsequently caused the gas generator rotating assembly to seize and resulted in the centrifugal compressor contacting the cover and creating the hole found in the component. Subsequent oil jet examinations revealed that coke pollution had obstructed the No. 2 oil jet. The lack of an oil filter precipitated the No. 2 oil jet obstruction and resulted in the axial compressor rear bearing deterioration. The resultant engine inefficiency caused by the bearing failure and obstructed oil jet led to the need for higher fuel flow, which eventually resulted in an overtemperature/high pressure turbine failure and seizure of the gas generator and subsequent flameout; this was confirmed by data downloaded from the digital engine control unit, which recorded exceedances in the gas generator and free turbine speeds and an increase in fuel flow. The manufacturer conducted the last maintenance, which was planned to be an overhaul of the accessory gearbox, 109.6 hours before the accident. During the maintenance, the oil filter was removed and discarded as part of the normal process for arrival inspection. A maintenance document review revealed that the overhaul was not due and that the manufacturer then sent the accessory gearbox back to the operator as is. However, the manufacturer did not inform the operator that it had removed the engine oil filter before returning the module, which is why no filter was found installed on the airplane.  

Quoted verbatim from the NTSB record.