Eurocopter AS 350 N5204X

Summary

On 27 October 2014 at about 23:04 local time, a Eurocopter AS 350 registered N5204X, operated by US Dept of Homeland Security, was involved in an accident near Bisbee, Arizona, 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

27 October 2014 at 23:04

Classification

Accident

Location

Bisbee, Arizona, United States

Coordinates

31.3983, -109.8017

Aircraft

Eurocopter AS 350

Registration

N5204X

Category

Helicopter

Year built

1998

Engines

1

Operator

US Dept of Homeland Security

Operating rule

Public Use

Phase of flight

Not recorded

Route

Fort Huachuca → Fort Huachuca

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR15TA027

1 person was seriously injured.

Failure of maintenance personnel to ensure adequate torque of a pneumatic control pipe (P2) fitting, which resulted in a loss of engine power during low altitude flight maneuvers.

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

Read the full NTSB narrative

The commercial pilot was maneuvering the turbine engine-equipped helicopter about 25 ft above ground level when the engine suddenly experienced a total loss of power. The pilot performed an autorotation, and the helicopter touched down hard and rolled over, coming to rest inverted. Examination of the engine revealed that the pneumatic control pipe (P2), which delivers air pressure from the centrifugal compressor on the engine to the fuel control unit (FCU), was disconnected at the engine fitting. The loss of P2 pressure to the FCU resulted in the FCU commanding the engine to spool down to ground idle speed by limiting the fuel flow. There was no evidence of malfunctions or anomalies on the pipe, threads, and union fastener. There was no evidence of torque stripe residue on the disconnected fitting, consistent with the likely scenario that, during past maintenance, the B-nut was not properly torqued and gradually vibrated off its attach fitting while in flight. The engine manufacturer had several caution notifications within multiple maintenance task documents to prevent removal of the P2 pipe during washing and the risk of an engine failure due to insufficient torque.

Quoted verbatim from the NTSB record.