Thursday, March 22, 2018

De Havilland Canada DHC-6-320 Twin Otter, N716JP, Bald Mountain Air Service Inc: Accident occurred March 20, 2018 in Deadhorse, Alaska

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

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Fairbanks, Alaska

Aviation Accident Preliminary Report - National Transportation Safety Board: 

Bald Mountain Air Service Inc:

Location: Deadhorse, AK

Accident Number: ANC18LA027
Date & Time: 03/20/2018, 1945 AKD
Registration: N716JP
Injuries: 1 Serious, 5 None
Flight Conducted Under: Part 135: Air Taxi & Commuter - Non-scheduled 

On March 20, 2018, about 1945 Alaska daylight time, a wheel-equipped, twin-engine, turbine-powered de Havilland DHC-6 (Twin Otter) airplane, N716JP, struck a pedestrian after takeoff from a remote sea ice airstrip, about 140 miles north of Deadhorse, Alaska. The pedestrian sustained serious injuries, and the airplane sustained substantial damage. The captain, first officer, and the three passengers on board the airplane were not injured. The flight was operated by Bald Mountain Air Service, Inc., Homer, Alaska, as a 14 Code of Federal Regulations (CFR) Part 135 visual flight rules (VFR) on-demand commercial flight when the accident occurred. Visual meteorological conditions prevailed at the airplane's point of departure, and a VFR flight plan was on file. The flight was en route to Deadhorse at the time of the accident.

During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 23, the accident airplane's captain said that the purpose of the flight was to provide ongoing logistical support of ICEX 2018, which involves, in part, U.S. Navy and U.K Royal Navy submarines operating beneath the frozen Arctic Ocean during a 5-week exercise. The captain stated that the flights used an airstrip on the sea ice that was lined on both sides with snow berms. The airstrip included one runway oriented north/south and an intersecting runway oriented east/west. He said that weather conditions at the time of the accident consisted of clear skies with ice pack haze. He noted that the sun was low on the horizon, resulting in shadows on the airstrip, and that flat light conditions made it difficult to discern topographical features.

The captain said that, after back-taxiing the airplane to the south end of the airstrip and just before beginning the takeoff roll to the north, both pilots saw the pedestrian standing near the departure end of the airstrip on the left side and near the intersection of the east/west runway. He said that during the takeoff roll, the airplane veered slightly to the left of centerline, so he applied differential engine power to correct the veer, and the airplane returned to the centerline. As the takeoff roll continued, the airplane subsequently became airborne, so he lowered the nose to remain within ground effect and gain airspeed before initiating a climb. He said that as the airspeed increased, he started to climb the airplane, then initiated a left turn. During the turn, both pilots said they heard a loud thump, which was immediately followed by an aileron control anomaly. The captain reported that he continued the left turn and subsequently entered a left downwind traffic pattern for an emergency landing to the north. The captain said that after landing, both pilots saw the pedestrian lying near a snow berm on the left side of the airstrip.

A postaccident examination of the airplane revealed substantial damage to the left wing and left aileron. The pedestrian sustained a serious head and neck injuries because of the collision, and he was subsequently medevacked to Anchorage, Alaska for treatment.

During a hospital room interview with the NTSB IIC, on March 25, the injured pedestrian, who was an employee of the Arctic Submarine Laboratory, reported that just before the two pilots boarded the airplane, it was agreed that he would position himself alongside the airstrip to get a photo of the airplane's departure. The pedestrian noted that, as the accident airplane approached, he positioned himself behind a 3- to 4-ft tall snow berm, which was clear of the airstrip. He said that, as the airplane's takeoff progressed, it did not climb as quickly as it had during previous departures. The pedestrian said that the last thing he remembered before the collision was seeing the airplane's left wing getting lower to the ground as the airplane continued to accelerate toward him. The next thing he remembered was waking up in the medevac helicopter.

The closest weather reporting facility was the Deadhorse Airport, 140 miles south of the accident site. The 1953 observation reported, in part: Wind, 270° at 12 knots; visibility, 9 statute miles with light snow; clouds and sky condition, 2,900 ft scattered, 4,600 ft overcast; temperature, minus 4° F; dew point, minus 9° F; altimeter, 30.47 inches of Mercury.

The airplane was equipped with a solid-state cockpit voice recorder (CVR), and a download of the CVR data is pending. 

Aircraft and Owner/Operator Information

Aircraft Manufacturer: DEHAVILLAND

Registration: N716JP
Model/Series: DHC 6 TWIN OTTER 300
Aircraft Category: Airplane
Amateur Built: No
Operating Certificate(s) Held: On-demand Air Taxi (135) 

Meteorological Information and Flight Plan

Conditions at Accident Site:

Condition of Light: Dusk
Observation Facility, Elevation: PASC
Observation Time: 1953 AKD
Distance from Accident Site: 140 Nautical Miles
Temperature/Dew Point: -20°C / -23°C
Lowest Cloud Condition: Scattered / 2900 ft agl
Wind Speed/Gusts, Direction: 12 knots, 270°
Lowest Ceiling: Overcast / 4600 ft agl
Visibility:  9 Miles
Altimeter Setting:  30.47 inches Hg
Type of Flight Plan Filed: VFR
Departure Point: Deadhorse, AK
Destination: Deadhorse, AK (PASC)

Wreckage and Impact Information

Crew Injuries: 2 None

Aircraft Damage: Substantial
Passenger Injuries: 3 None
Aircraft Fire: None
Ground Injuries: 1 Serious
Aircraft Explosion: None
Total Injuries: 1 Serious, 5 None
Latitude, Longitude:   (est)

A man survived being struck by a plane that was taking off from sea ice 140 miles north of Deadhorse on the Beaufort Sea, according to the National Transportation Safety Board.

The man, whose name has not been released, worked at the Arctic Submarine Laboratory supporting exercises during which U.S. and British navy submarines surface through the sea ice north of Alaska. That’s according to a preliminary report from the NTSB, which continues to investigate the March 20 plane strike.

NTSB investigator Clint Johnson said the man was trying to snap a photo for his kids and was standing behind a snow berm next to an ice runway as the de Havilland DHC-6 Twin Otter took off.

“He was going to be leaving the ice within the next couple of days,” Johnson said. “He did want to get a picture of these small Lego figurines with the airplane in the background.”

The man told Johnson he talked to the pilot about taking the photo beforehand, though Johnson said the pilot, in a separate interview, did not recall the conversation.

Johnson described what the man says he saw as the plane started taking off:

“The airplane accelerated toward him. It didn’t climb as he anticipated,” Johnson said. “The airplane started a turn to the left, which means the left wing got closer to the ground. The next thing he knew is he saw the wing, and that’s all that he remembers. He remembered waking up in the medivac helicopter on the way to Deadhorse.”

According to the NTSB report, the pilot and co-pilot heard a loud thump, and they had trouble with the plane’s controls. They made an emergency landing back on the airstrip and found the man with serious head and neck injuries.

While the rest of the camp has since been removed from the ice, Johnson said the plane was not flyable and was left behind. He said the Twin Otter was still there as of Tuesday morning, a week later, with substantial damage to its left wing, and there were plans to use a heavy-lift helicopter to retrieve it from the drifting and deteriorating sea ice.

The plane’s owner, Homer-based Bald Mountain Air Service, released a written statement about the incident Tuesday but did not answer questions about the plane’s status.

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