Bell 47G 2 N975BH

Summary

On 30 July 2016 at about 20:05 local time, a Bell 47G 2 registered N975BH, operated by Experimental Aircraft Association, was involved in an accident near Oshkosh, Wisconsin, United States. 3 people were 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

30 July 2016 at 20:05

Classification

Accident

Location

Oshkosh, Wisconsin, United States

Nearest airport

Wittman Rgnl (OSH)

Coordinates

43.9914, -88.5597

Aircraft

Bell 47G 2

Registration

N975BH

Category

Helicopter

Year built

1959

Engines

1

Operator

Experimental Aircraft Association

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Oshkosh → Oshkosh

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN16LA294

Nobody was injured.

The loosening and separation of the throttle linkage nut, which resulted in a loss of throttle control and subsequent hard landing after autorotation.

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

Read the full NTSB narrative

The airline transport pilot maneuvered the helicopter on the downwind leg of the airport traffic pattern and attempted to reduce power for landing; however, the engine power remained excessively high. The pilot attempted to further reduce the engine power by turning off one magneto and applying carburetor heat, but the power remained too high to safely descend. The pilot then entered a sideslip, which allowed the helicopter to descend to about 100 ft above the runway. He turned the engine power off and autorotated to the ground. The helicopter landed hard in a tail-low attitude. The main rotor struck the tail and the tail rotor assembly separated from the helicopter. A postaccident examination found that the throttle linkage nut had loosened and separated from its fitting, causing the throttle to remain open. The helicopter's maintenance manual did not specify a torque value for the throttle linkage nut, and there were no maintenance procedures requiring the nut to be loosened or removed during overhaul. The pilot indicated that a complete overhaul of the helicopter was completed about 37 hours before the accident flight.  

Quoted verbatim from the NTSB record.