Air Tractor AT802 N397AS

Summary

On 14 August 2018 at about 22:00 local time, a Air Tractor AT802 registered N397AS, operated by Air Spray USA, Inc., was involved in an accident near Northport, Washington, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 August 2018 at 22:00

Classification

Accident

Location

Northport, Washington, United States

Coordinates

48.9803, -118.0178

Aircraft

Air Tractor AT802

Registration

N397AS

Category

Airplane

Year built

2014

Engines

1

Operator

Air Spray USA, Inc.

Operating rule

Public Use

Phase of flight

Not recorded

Route

Deer Park → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR18LA222

1 person was seriously injured.

A total loss of engine power during a climb due to an accumulation of molten environmental particles, the source of which could not be determined based on the available evidence, which resulted in a forced landing.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The accident airplane was one of three public aircraft that were supporting firefighting operations. The three airplanes had made four successful water drops and had just scooped water from a river to make a fifth drop. The airplanes were in a climb en route to the drop location when the pilot of the accident airplane heard a “loud bang” followed by a total loss of engine power. The pilot made a forced landing to treetops in a heavily forested area. During the on-site examination, a coat of oil was observed on the cowling and one of the wings. Damage was also observed to the engine. The engine examination revealed that a second-stage power turbine blade exhibited fatigue signatures, and molten debris was identified throughout the engine. The debris was subsequently identified as environmental particles, but the source of the debris was not determined from the available evidence for this investigation. The loss of engine power was likely due to the accumulation of foreign melted environmental debris on the engine’s hot section components, which resulted in the first- and second-stage power turbine blades fracturing from tensile overload.

Quoted verbatim from the NTSB record.