Hughes 369D N11AS

Summary

On 24 April 2007 at about 12:30 local time, a Hughes 369D registered N11AS, operated by Aerial Solutions Incorporated, was involved in an accident near Whiteville, North Carolina, United States. 2 people were on board and one 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

24 April 2007 at 12:30

Classification

Accident

Location

Whiteville, North Carolina, United States

Coordinates

34.1061, -78.7025

Aircraft

Hughes 369D

Registration

N11AS

Category

Helicopter

Engines

1

Operator

Aerial Solutions Incorporated

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Whiteville → Whiteville

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ATL07LA079

1 person had minor injuries.

A partial loss of engine power due to fatigue fracture of the power turbine governor spring, causing a false pneumatic signal to the fuel control and a corresponding reduction in fuel flow.

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

Read the full NTSB narrative

According to the pilots, the helicopter was at an altitude between 400 and 500 feet above ground level and at an airspeed between 75 and 80 knots when the engine lost power. The instructor-pilot took control of the helicopter, jettisoned the external load, and autorotated to a nearby corn field. He said that the engine "didn't sound like it was running and the engine out was activated." The helicopter touched down and slid 6 to 8 feet when one of the skids dug into the earth. The helicopter turned to the left about 45 degrees and rolled over on its right side. It was later found that the power turbine governor (PTG) spring had fractured in fatigue. The fracture originated from a drawing mark and was the result of deficiencies in the manufacturing process. The PTG spring "provides force opposing those exerted by rotating flyweights on the position of the governor lever. Failure of the spring would result in a false pneumatic signal to the fuel control and a corresponding reduction in fuel flow. The effect of the false pneumatic signal would be a pronounced reduction in fuel flow. At the reduced fuel flow, the engine could not sustain flight, and the symptoms of the reduced fuel flow might easily be interpreted by the pilot as an engine failure."

Quoted verbatim from the NTSB record.