WPR09LA010

NTSB accident investigation · Bell 206B · Cougar, WA · October 10, 2008

Accident · Serious injuriesLimited investigationFinal report
Date
October 10, 2008, 10:30 local (17:30 UTC)
Place
Cougar, WA
Injuries
1 serious
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N206CHBell 206B
Defining event
Maneuvering-low-alt flying: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed · report December 24, 2008
Report
Approved by Office Director
NTSB office
Western Pacific Region
Parties
Portland FSDO
FAA report
20081010848849A
Case key
69274

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The NTSB’s determination of the probable cause, and any contributing factors.

The pilot's failure to maintain clearance between his external load and trees while maneuvering. Contributing to the accident were hilly terrain and trees.

Findings · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings.

Analysis

Soon after the helicopter lifted an external load of tree branches and began to fly an uphill route to the central collection point, the long-line became tangled in the trees below the flightpath. As the pilot attempted to continue up the hill toward a landing site, the helicopter's low-rotor rpm horn sounded, and soon thereafter its nose pitched down, and it impacted the ground near the bottom of a steep ravine. Although the long-line was not attached to the helicopter when it crashed, its proximity to the accident site indicated that it was released shortly before the impact. Neither the on-site or the follow-up inspection of the helicopter revealed any evidence of an anomaly in the airframe, engine, or flight control system.

Factual narrative

The factual narrative446 words

On October 10, 2008, about 1030 Pacific daylight time, a Bell 206B helicopter, N206CH, impacted the ground while maneuvering in hilly terrain near Cougar, Washington. The commercial pilot received serious injuries, and the helicopter, which was owned and operated by Northwest Helicopters, sustained substantial damage. The 14 Code of Federal Regulations (CFR) Part 133 rotorcraft external load flight, which departed Olympia, Washington, about an hour and fifteen minutes prior to the accident, was being operated in visual meteorological conditions. A company visual flight rules (VFR) flight plan had been filed. According to witnesses on the ground, the helicopter was hauling tree limbs uphill to a central pickup point when the load on the end of the 60-foot cable got caught in the trees that the helicopter was flying over. According to the pilot, when the load got about 20 feet above the ground, the helicopter did a "very quick" 15 to 20 degree roll to the right, and then quickly rolled back to the level position. At that time, the pilot looked outside "to see if the load was tangled," but after the accident he could not remember what he had observed. The pilot's next recollection was looking forward and slightly uphill, and that he could not move the cyclic laterally to the left from its position of about 10 degrees right of center. At that point he continued to try to fly uphill to a dirt road, but had "little control' over the helicopter. As he neared the road, the low-rotor horn came on, and shortly thereafter, at an altitude that the pilot estimated as 20 to 40 feet above the terrain, the helicopter yawed to the right and pitched nose down. At that time, according to the pilot, he knew ground impact was imminent, so he "rolled off the throttle to at least the idle position." According to the witnesses, the helicopter impacted the terrain near the bottom of a steep tree-covered ravine. Although the pilot does not remember whether he did so, the long-line was released from the helicopter prior to the impact. It was located about 75 feet from the crash site, with the end that was attached to the helicopter lying closest to the site. A Federal Aviation Administration (FAA) Inspector from the Portland Flight Standards District Office (FSDO) responded to the accident site. That individual talked with witnesses, and performed an on-site inspection of the helicopter. The helicopter was then recovered to the hangar of the operator, where it underwent a further FAA inspection. Neither the on-site nor the follow-up inspection found any indication of an airframe, engine, or flight control anomaly that would have contributed to the accident sequence.

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident.

Aircraft

Registration
N206CH
Reported as
Bell 206B
Category
Helicopter
Serial number
1735
Airframe hours
12,242
Engine
Rolls-Royc 250-C20B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
External load · Part 133
Operator
Northwest Helicopters
Registered owner
Northwest Helicopters I Inc
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · October 6, 2008
Departed
KOLM · Olympia, WA
Destination
Cougar, WA
Flight plan
Company VFR

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
50
Injuries
Serious
Certificates
Flight instructor, Commercial, Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
February 29, 2008
Seat
Right
Flight hours
9,858 total · 3,450 in this make and model · 9,750 as pilot in command · 159 in the last 90 days · 51 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Visibility
10 statute miles
Lowest ceiling
None
Temperature
45 °F

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.