- Date
- August 5, 2008, 19:41 local (Aug 6, 2008, 02:41 UTC)
- Place
- Weaverville, CA
- Injuries
- 9 fatal, 4 serious
- Damage
- Destroyed
- Phase of flight
- Initial climb
- Aircraft
- N612AZSikorsky S-61N
- Defining event
- Initial climb: Collision during takeoff/land
- Weather
- Visual (VMC)
- Status
- Completed · report January 25, 2011
- Report
- Board-adopted at Board Meeting
- Investigation class
- Class 1
- Parties
- Washington, D.C., AAI-100
- Safety recommendations
- Yes
- FAA report
- 20080805857529A
- Case key
- 68616
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The following actions by Carson Helicopters: 1) the intentional understatement of the helicopter's empty weight, 2) the alteration of the power available chart to exaggerate the helicopter's lift capability, and 3) the practice of using unapproved above-minimum specification torque in performance calculations that, collectively, resulted in the pilots relying on performance calculations that significantly overestimated the helicopter's load-carrying capacity and did not provide an adequate performance margin for a successful takeoff; and insufficient oversight by the U.S. Forest Service and the Federal Aviation Administration.
Contributing to the accident was the failure of the flight crewmembers to address the fact that the helicopter had approached its maximum performance capability on their two prior departures from the accident site because they were accustomed to operating at the limit of the helicopter’s performance.
Contributing to the fatalities were the immediate, intense fire that resulted from the spillage of fuel upon impact from the fuel tanks that were not crash resistant, the separation from the floor of the cabin seats that were not crash resistant, and the use of an inappropriate release mechanism on the cabin seat restraints.
Findings · 12
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The Safety Board's full report is available at http://www.ntsb.gov/publictn/A_Acc1.htm. The Aircraft Accident Report number is NTSB/AAR-10-06.
On August 5, 2008, about 1941 Pacific daylight time, a Sikorsky S-61N helicopter, N612AZ, impacted trees and terrain during the initial climb after takeoff from Helispot 44 (H-44), located at an elevation of about 6,000 feet in mountainous terrain near Weaverville, California. The pilot-in-command, the safety crewmember, and seven firefighters were fatally injured; the copilot and three firefighters were seriously injured. Impact forces and a postcrash fire destroyed the helicopter, which was being operated by the U.S. Forest Service (USFS) as a public flight to transport firefighters from H-44 to another helispot. The USFS had contracted with Carson Helicopters, Inc. (CHI) of Grants Pass, Oregon, for the services of the helicopter, which was registered to CHI and leased to Carson Helicopter Services, Inc. of Grants Pass. Visual meteorological conditions prevailed at the time of the accident, and a company visual flight rules flight plan had been filed.
Factual narrative
The Safety Board's full report is available at http://www.ntsb.gov/publictn/A_Acc1.htm. The Aircraft Accident Report number is NTSB/AAR-10-06.
On August 5, 2008, about 1941 Pacific daylight time, a Sikorsky S-61N helicopter, N612AZ, impacted trees and terrain during the initial climb after takeoff from Helispot 44 (H-44), located at an elevation of about 6,000 feet in mountainous terrain near Weaverville, California. The pilot-in-command, the safety crewmember, and seven firefighters were fatally injured; the copilot and three firefighters were seriously injured. Impact forces and a postcrash fire destroyed the helicopter, which was being operated by the U.S. Forest Service (USFS) as a public flight to transport firefighters from H-44 to another helispot. The USFS had contracted with Carson Helicopters, Inc. (CHI) of Grants Pass, Oregon, for the services of the helicopter, which was registered to CHI and leased to Carson Helicopter Services, Inc. of Grants Pass. Visual meteorological conditions prevailed at the time of the accident, and a company visual flight rules flight plan had been filed.
Aircraft
- Registration
- N612AZ
- Reported as
- Sikorsky S-61N
- Category
- Helicopter
- Engines
- General Electric CT58-140, turbo shaftGeneral Electric CT58-140, turbo shaft
- Damage
- Destroyed
- Fire
- On-Ground
- Flight
- Public aircraft - federal · Public use
- Operator
- USDA Forest Service
- Departed
- NONE · Weaverville, CA
- Destination
- NONE
- 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 · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 54
- Injuries
- Fatal
- Certificates
- Commercial, Airline transport
- Flight hours
- 20,286 total · 8,166 in this make and model
- Role
- Co-pilot
- Injuries
- Serious
Weather
- Conditions
- Visual (VMC)
- Wind
- 150° at 7 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 91 °F, dew point 36 °F
- Altimeter
- 29.82 inHg
- Observed at
- RDD
Docket · 236
The files NTSB released with the investigation on September 16, 2009, on NTSB’s docket system: statements, records, photos and specialists’ reports.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.