Eurocopter EC130 B4 N334AM

Summary

On 2 January 2013 at about 18:45 local time, a Eurocopter EC130 B4 registered N334AM, operated by Air Methods Corp, was involved in an accident near Seminole, Oklahoma, United States. 4 people were on board and 4 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

2 January 2013 at 18:45

Classification

Accident

Location

Seminole, Oklahoma, United States

Coordinates

35.3072, -96.5806

Aircraft

Eurocopter EC130 B4

Registration

N334AM

Category

Helicopter

Engines

1

Operator

Air Methods Corp

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Seminole → Okemah

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN13FA121

4 people were seriously injured.

The loss of engine power due to ice ingestion. Contributing to the accident was maintenance personnel’s delayed decision to install the helicopter's engine inlet cover until after the engine had been exposed to moisture and freezing temperatures and their inadequate daily preflight/airworthiness checks, which did not detect the ice formation.

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

Read the full NTSB narrative

The pilot reported hearing a sound like something had struck the helicopter shortly after departure while about 1,600 to 1,700 feet mean sea level. The engine lost power, and the pilot performed an autorotation to a field. While maneuvering to land, he saw a barbed wire fence obstructing the intended landing area, so he maneuvered the helicopter to clear the fence. The helicopter subsequently cleared the fence and landed hard in a field. Engine examination revealed that the four axial compressor blades exhibited significant deformation on the outboard tips of their leading edges in the direction opposite of normal rotation consistent with the ingestion of soft body foreign object debris, such as ice. A subsequent engine run did not detect any preimpact anomalies that would have precluded normal operation. For 3 days before the accident flight, the helicopter was parked outside without its engine cover installed and was exposed to light drizzle, rain, mist, and fog. The engine inlet cover was installed the day before the accident at an unknown time. The helicopter remained outside and exposed to freezing temperatures throughout the night until 2 hours before the flight. Although the helicopter was maintained in a ready status on the helipad and maintenance personnel performed daily preflight/airworthiness checks, the inlet to the first-stage of the axial compressor was not inspected to ensure that it was free of ice in accordance with the Aircraft Maintenance Manual. Based on the weather conditions that the helicopter was exposed to during the 3 days before the accident, it is likely that ice formed in the engine air inlet before the flight and that, when the pilot increased the engine power during takeoff, the accumulated ice separated from the inlet and was ingested by the engine and damaged the compressor blades.

Quoted verbatim from the NTSB record.