ANC20LA069

NTSB accident investigation · Air Tractor AT802 · Birch Creek, AK · July 14, 2020

Accident · No injuriesClass 3 · LimitedFinal report
Date
July 14, 2020, 15:55 local (23:55 UTC)
Place
Birch Creek, AK
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N80166Air Tractor AT802
Defining event
Landing-landing roll: Loss of control on ground
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Alaska Regional Office
Parties
Fireboss LLC/Wipaire, Inc., Air Tractor, Inc., Bureau of Land Management, Dauntless Air, Wipaire, Inc., Office of Aviation Services
FAA report
20200714016669A
Case key
101615

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

A loss of control for undetermined reasons while on the surface of the water during scoop operations in support of wildland firefighting operations.

Findings · 2

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.

Performance/control parameters: directional controlAircraft › Aircraft oper/perf/capability · Not attained/maintainedAir Tractor AT-802A: 10 casesAll aircraft: 3,958 casesProbable cause
Not determinedNot determined › Not determined · Unknown/Not determinedAir Tractor AT-802A: 7 casesAll aircraft: 2,247 casesProbable cause

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 mission-specific modified airplane was used to support wildland firefighting operations. It was equipped with amphibious floats that routed water through a dual scoop system to a hopper located in the airplane. The scoops could be manually deployed by a switch located on the control stick. According to the pilot, on the 28th scoop of the day, he touched down on the surface of the water and deployed the scoops to begin filling the airplane’s hopper when the airplane veered to the right. In an effort to correct for the veer, he released the scoop switch and applied left rudder to no avail. He retarded the throttle and applied reverse thrust as the airplane began to impact trees located on the lake’s shoreline. The airplane came to rest upright in a marshy area on the lake’s shoreline sustaining substantial damage to the right wing. A series of detailed examinations of the airplane, including its water scoop system, revealed no preaccident mechanical failures or malfunctions that would have precluded normal operations.

Factual narrative

On July 14, 2020, about 1555 Alaska daylight time, an Air Tractor AT802A airplane, N80166, sustained substantial damage when it was involved in an accident near Birch Creek, Alaska. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 firefighting flight. The mission-specific modified airplane was used to support wildland firefighting operations. The airplane was equipped with Wipline 10000 amphibious floats. Scoops/probes could be manually deployed by a switch located on the control stick of the airplane that actuated an electrically driven hydraulic pump; when the switch was released the scoops would retract. Water was routed through the scoops located on each float to a hopper located in the aircraft. In addition, the airplane was equipped with an asymmetric scoop warning system. In the event of an asymmetric scoop deployment, an audible warning “scoop malfunction” would sound, and a red warning light would illuminate on the instrument panel. According to the pilot, on the 28th scoop of the day, he touched down on the surface of the water and deployed the scoops to begin filling the airplane’s hopper when the airplane veered to the right. In an effort to correct for the veer he released the scoop switch and applied left rudder to no avail. He retarded the throttle and applied reverse thrust as the airplane began to impact trees located on the lake’s shoreline. The airplane came to rest upright in a marshy area on the lake’s shoreline sustaining substantial damage to the right wing. A series of postaccident examinations of the airplane including its fuel system, flight control system and water scoop system revealed no preaccident mechanical failures or malfunctions that would have precluded normal operations. Control continuity was established for all flight and engine controls.

Aircraft

Registration
N80166
Reported as
Air Tractor AT802 (A)
Category
Airplane
Serial number
802A-0685
Built
2017
Airframe hours
349.5
Engine
Pratt & Whitney PT6A-67F, turbo prop
Damage
Substantial damage
Flight
Firefighting · Part 137
Operator
Aero Spray Inc
Registered owner
Aero Spray Inc
Airworthiness certificate
Special, Restricted (Special)
Last inspection
100 hour · June 16, 2020
Departed
PAFB · Fairbanks, AK
Destination
PAFB · Fairbanks, AK
Flight plan
Company VFR
Equipment
Satellite tracking device, Stall warning system, ADS-B, Data recorder, Handheld GPS, Onboard weather

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

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
50
Injuries
None
Certificate
Commercial
Airplane ratings
Multi-engine land, Single-engine land, Single-engine sea
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
March 1, 2020
Seat
Single
Restraint
5-point
Flight hours
11,000 total · 2,000 in this make and model · 10,700 as pilot in command · 35 in the last 90 days · 30 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
290° at 4 knots
Visibility
10 statute miles
Temperature
72 °F, dew point 43 °F
Altimeter
29.79 inHg

Docket · 12

The files NTSB released with the investigation on March 16, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 15.3 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.