Sunday, September 29, 2019

Collision During Takeoff: de Havilland Canada DHC-6-320 Twin Otter, N716JP; 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 Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf 


Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms 
 
http://registry.faa.gov/N716JP




Location: Deadhorse, PO
Accident Number: ANC18LA027
Date & Time: 03/20/2018, 1942 AKD
Registration: N716JP
Aircraft: DEHAVILLAND DHC 6 TWIN OTTER
Aircraft Damage: Substantial
Defining Event: Collision during takeoff/land
Injuries: 1 Serious, 5 None
Flight Conducted Under: Part 135: Air Taxi & Commuter - Non-scheduled 

On March 20, 2018, about 1942 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 involved, 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 2,500-foot-long by 75-foot-wide 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 behind a snow berm on the left side of the airstrip. At the end of the telephone interview, when asked by the NTSB IIC if it had been prearranged to have the pedestrian near the departure end of the airstrip during the departure, the captain said, in part: "I don't recall." The captain also reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

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 medevaced to Anchorage, Alaska, for treatment.

The accident co-pilot elected to submit a written statement in place of an interview with the NTSB IIC. Written statements from both pilots are included in the public docket for this accident.

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, he discussed with the captain that he would position himself alongside the airstrip to get a photo of the airplane's departure for his children. The pedestrian added that the purpose of taking the photo was to have two figurines in the foreground, and the departing airplane in the background, so he placed the figurines on a 3- to 4-ft tall snow berm on the left side of the airstrip. He said that, as he watched the accident airplane approach, he positioned himself behind the snow berm and well 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 it began a left turn and flew toward him, as it continued to accelerate. 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 it was sent it to the NTSB vehicle recorder laboratory in Washington, D.C., for audition and review. After review, it was determined that the CVR failed to capture the events of the accident. No CVR listening group was convened, and no CVR transcript was created.

The accident sequence was recorded by a security video camera mounted on one of the temporary camp structures positioned to the west of the north/south airstrip. A copy of the video was reviewed by the NTSB IIC, and it contained about 1 hour and 34 minutes of imagery. The video was recorded in low and flat light conditions making it difficult to discern topographical features on the ice. About the 14-minute time stamp, the pedestrian can be seen standing near some equipment and a snowmachine that was parked next to the airstrip. About 1 minute later, the low flying airplane enters the field of view, traveling from right-to-left, while flying in a straight and level attitude. As the low flying airplane nears the pedestrian, the airplane begins a steep left turn, and the left-wing lowers. The left wing of the airplane subsequently struck the pedestrian, and the airplane continued to the left, and out of the field of view. A clip of the accident video is included in the public docket for this accident.



Pilot Information

Certificate: Airline Transport; Commercial
Age: 32, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 01/23/2018
Occupational Pilot: Yes
Last Flight Review or Equivalent: 12/03/2017
Flight Time:  5724 hours (Total, all aircraft), 1024 hours (Total, this make and model)

Co-Pilot Information

Certificate: Commercial
Age: 28, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s):
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 08/16/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time:  733 hours (Total, all aircraft), 117 hours (Total, this make and model), 228 hours (Pilot In Command, all aircraft)


Aircraft and Owner/Operator Information

Aircraft Make: DEHAVILLAND
Registration: N716JP
Model/Series: DHC 6 TWIN OTTER
Aircraft Category: Airplane
Year of Manufacture: 1977
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 527
Landing Gear Type: Tricycle
Seats: 2
Date/Type of Last Inspection: 03/19/2018, Continuous Airworthiness
Certified Max Gross Wt.: 12500 lbs
Time Since Last Inspection:
Engines: 2 Turbo Prop
Airframe Total Time: 29299.8 Hours as of last inspection
Engine Manufacturer: Pratt & Whitney
ELT: C126 installed, not activated
Engine Model/Series: PT6A-27
Registered Owner: BALD MOUNTAIN AIR SERVICE INC
Rated Power: 680 hp
Operator: BALD MOUNTAIN AIR SERVICE INC
Operating Certificate(s) Held: On-demand Air Taxi (135)

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Dusk
Observation Facility, Elevation: PASC
Distance from Accident Site: 140 Nautical Miles
Observation Time: 1953 AKD
Direction from Accident Site: 180°
Lowest Cloud Condition: Scattered / 2900 ft agl
Visibility:  9 Miles
Lowest Ceiling: Overcast / 4600 ft agl
Visibility (RVR):
Wind Speed/Gusts: 12 knots /
Turbulence Type Forecast/Actual: 
Wind Direction: 270°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 30.47 inches Hg
Temperature/Dew Point: -20°C / -23°C
Precipitation and Obscuration: Light - Snow
Departure Point: Deadhorse, AK
Type of Flight Plan Filed: VFR
Destination: Deadhorse, AK (PASC)
Type of Clearance: None
Departure Time: 1940 AKD
Type of Airspace: 

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: 72.300833, -148.794722

2 comments:

Anonymous said...

Remember not to stand next to runway when planes are present. Pedestrian was very fortunate, as were the plane occupants.
I guess the guy did not get the photo for his kids.

Anonymous said...

Pilots fault.... Cant cure stupid or reckless! Great photo op though! :-)