Air Tractor AT802 N816FF

Summary

On 18 July 2017 at about 22:10 local time, a Air Tractor AT802 registered N816FF, operated by C & C Flying Service Inc., was involved in an accident near Reyno, Arkansas, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 July 2017 at 22:10

Classification

Accident

Location

Reyno, Arkansas, United States

Coordinates

36.3589, -90.8161

Aircraft

Air Tractor AT802

Registration

N816FF

Category

Airplane

Year built

2017

Engines

1

Operator

C & C Flying Service Inc.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Reyno → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN17LA284

Nobody was injured.

The pilot’s inadvertent use of the propeller control, which caused the propeller to feather while in flight with the engine still operating, resulting in a loss of thrust and a subsequent forced landing.

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

Read the full NTSB narrative

The pilot was returning to the landing strip after an uneventful spray flight when he noticed a rapid increase in engine torque shortly after he made a power reduction. The pilot stated that he “looked at my levers and pushed the prop lever all the way forward.” According to the pilot, there was insufficient thrust to maintain altitude and he made a forced landing in an open field. The airplane’s left wing impacted the ground during landing and the airplane skidded sideways to a stop. The right wingtip, right aileron, and right elevator were substantially damaged. Examination and bench testing revealed no evidence of a mechanical malfunction or failure that would have precluded normal engine operation. Engine control continuity was confirmed from the cockpit levers to their respective engine components, and the engine controls moved smoothly through their full range of motion. An analysis of the airplane’s engine monitor data revealed that the pilot had mistakenly moved the cockpit propeller lever instead of the power lever while he maneuvered to land. When the pilot moved the propeller control aft it increased propeller pitch which, in turn, decreased propeller speed (Np). As Np decreased there was a corresponding increase in engine torque. The data analysis revealed that Np decreased to the point where the constant speed unit (CSU) feather valve dumped oil pressure, and the propeller feathered. Engine torque then rapidly increased above the 5,100 ft-lbs limitation. Shortly after the propeller feathered, there was a rapid increase in fuel flow and engine torque, consistent with the pilot moving the power lever full forward with the propeller still feathered. The gas generator speed (Ng) and fuel flow remained relatively constant and the engine torque remained above 6,600 ft-lbs until the engine was shut down after the accident.

Quoted verbatim from the NTSB record.