What happened
On May 6, 2016, at approximately 1900 Alaska daylight time, an Airbus AS 350 B2 helicopter, registration N94TH, collided with snow-covered mountains about 4 miles southeast of Skagway, Alaska. The aircraft was performing a visual flight rules (VFR) internal-cargo flight for TEMSCO Helicopters, Inc., transporting personnel and dogs to a remote camp on the Denver Glacier.
The pilot had completed several roundtrip flights that day to support Alaska Icefield Expeditions, Inc. While earlier flights had been delayed by low ceilings, the pilot resumed operations as weather improved. However, during the sixth trip, the pilot transported one employee and 12 dogs to the glacier. Upon arrival, the weather was deteriorating, with increasing winds and snow. Although the pilot informed the dog camp manager that he would not return for the final scheduled trip due to the weather, he departed the glacier at 1852.
Flight tracking data indicated the helicopter performed multiple 360-degree turns after departing the camp. Approximately eight minutes after departure, the aircraft impacted terrain near a frozen glacial lake, about 2 miles northeast of the dog camp. The pilot sustained 1 fatal injury.
The investigation
Investigators examined the wreckage and found the fuselage lying on its left side with the tailboom separated. The cockpit sustained extensive damage, and the engine and rotor systems showed damage consistent with a rollover under power following the initial impact.
An examination of the cargo configuration revealed that two wooden dog boxes were secured to the cabin floor using two cargo straps. During the impact, these straps failed, causing the boxes to shift forward and strike the back of the pilot's fiberglass seat.
Maintenance records for the aircraft showed no evidence of uncorrected mechanical discrepancies. The investigation also noted that the total weight of the cargo, including the boxes, shoring, and straps, had exceeded the structural limitation of 682 pounds for the cabin floor on several flights that day, as the weight of the dogs alone was not being added to the weight of the transport equipment in the official records.
Findings
- The pilot continued visual flight into an area of instrument meteorological conditions (IMC), leading to a loss of visual reference and controlled flight into terrain.
- The pilot experienced self-induced pressure to complete the scheduled series of flights.
- The operator failed to maintain proper operational control, as the base manager did not terminate flight operations after the pilot reported encountering icing conditions during a previous flight.
- The aircraft was operating in weather conditions that were deteriorating, with increasing wind and snow.