Tuesday, May 23, 2017

Eurocopter AS-350B-2, N207CH, Coastal Helicopters Inc: Accident occurred May 22, 2017 in Juneau, Alaska

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entities:

Federal Aviation Administration / Flight Standards District Office; Juneau, Alaska
Bureau d'Enquetes et d'Analyses; Paris
Airbus Helicopters (Advisor); Grand Prairie, Texas
Turbomeca USA (Advisor); Grand Prairie, Texas
Coastal Helicopters; Juneau, Alaska

Aviation Accident Preliminary Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Coastal Helicopters Inc: http://registry.faa.gov/N207CH

NTSB Identification: ANC17LA025 

Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Monday, May 22, 2017 in Juneau, AK
Aircraft: AIRBUS AS350, registration: N207CH
Injuries: 4 Minor, 3 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final
report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On May 22, 2017, about 1805 Alaska daylight time, an Airbus (formerly Eurocopter) AS350B2 helicopter, N207CH, sustained substantial damage during a collision with remote mountainous snow-covered terrain while en route to Juneau, Alaska, about 21 miles northwest of Juneau. Of the seven occupants on board, the commercial pilot and three passengers sustained minor injuries, and three passengers were not injured. The helicopter was registered to, and operated by, Coastal Helicopters, Inc., Juneau, as a day, visual flight rules (VFR) flight under the provisions of 14 Code of Federal Regulations Part 135 as an on-demand sightseeing tour flight. Degraded visual meteorological conditions were reported on the Herbert Glacier at the time of the accident, and company flight following procedures were in effect. The flight originated from the Juneau International Airport, Juneau at 1743.

During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on May 25, the pilot reported that she departed from the Juneau International Airport to pick up cruise ship passengers from a remote dog sledding camp situated on the Herbert Glacier. The sightseeing tour flight, which the cruise ship passengers had purchased from the cruise line as a shore excursion, overflew remote mountainous snow-covered terrain in the Tongass National Forest, and involved a landing on the Herbert Glacier for a dog sledding tour. At 1757, she landed at the dog sledding camp, picked up six passengers, and headed back to the Juneau International Airport. 

While en route back to Juneau, about 3/4 mile from the dog sledding camp, and while descending over an area of featureless, snow-covered ice field, the pilot reported that she could maintain visual reference with a rock wall on the right side of the helicopter. As the flight progressed downslope, she saw an area ahead that was "fogged in" and she chose to return to the dog sledding camp. While conducting a slow 180° turn to the right, the helicopter subsequently struck the snow-covered ice field, and it eventually came to rest inverted.

After all the occupants had egressed from the helicopter, the pilot utilized a handheld radio to request emergency assistance from the dog sledding camp. The personnel at the dog sledding camp contacted the operator's headquarters in Juneau, who sent another company helicopter to extract the pilot and passengers from the accident site.

According to the pilot, in addition to the fog, flat light conditions were present at the time of the accident. 

According to NTSB Safety Alert SA-052 Visual Illusions, flat light conditions are characterized, in part as: "…flat light occurs when the sky is overcast, especially over snow-covered terrain and large bodies of water. In flat light conditions, no shadows are cast and terrain features and other visual cues are masked, making it difficult for pilots operating under VFR to perceive depth, distance, or altitude." 

The helicopter sustained substantial damage to the fuselage, the main rotor system, the tailboom, and the tail rotor system. The wreckage was recovered and transported to a secure facility.

The pilot reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.

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