Bell 206B N6181A

Summary

On 12 September 2016 at about 20:45 local time, a Bell 206B registered N6181A, operated by Hi Line Helicopters, Inc., was involved in an accident near Rockport, Washington, United States. 2 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

12 September 2016 at 20:45

Classification

Accident

Location

Rockport, Washington, United States

Coordinates

48.8322, -121.1544

Aircraft

Bell 206B

Registration

N6181A

Category

Helicopter

Year built

1993

Engines

1

Operator

Hi Line Helicopters, Inc.

Operating rule

Public Use

Purpose of flight

External Load

Phase of flight

Not recorded

Route

Rockport → Rockport

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR16LA188

Nobody was injured.

The pilot's failure to maintain helicopter control while on the ground, which resulted in mast bumping.

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

Read the full NTSB narrative

The commercial pilot reported that, after landing the helicopter on a flat area in remote, mountainous terrain, she reduced the throttle to the idle position and the left front seat passenger exited the helicopter. The pilot reported that, while the passenger was securing the door, the helicopter started to oscillate laterally. The pilot adjusted the flight controls and increased the throttle, and the lateral oscillations stopped. The passenger stated that the helicopter "bounced and lurched" while he was securing the door but that the tail rotor did not come in contact with any objects or terrain. The pilot subsequently shut down the engine and conducted a postflight inspection, which revealed substantial damage to the transmission system. The pilot stated there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. Damage observed on the pylon mount assembly and main rotor mast was consistent with a mast bumping event, during which the static stops contact the mast due to excessive rotor blade flapping. During ground operations with the rotor turning, the main rotor may be affected by wind gusts and flap to its limits, resulting in a light static stop-to-mast contact. In such an event, mast bumping may manifest itself as a light shudder felt throughout the helicopter. The more extreme the flapping, the more severe the shudder. Mast bumping can also occur during ground operation if the cyclic is incorrectly positioned or is moved sufficiently to tilt the rotor disc to an extreme position.

Quoted verbatim from the NTSB record.