Air Tractor 402A N4506L

Summary

On 26 June 2003 at about 13:52 local time, a Air Tractor 402A registered N4506L, operated by USDA/Forest Service, was involved in an accident near Pearisburg, Virginia, 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

26 June 2003 at 13:52

Classification

Accident

Location

Pearisburg, Virginia, United States

Coordinates

37.2603, -80.8072

Aircraft

Air Tractor 402A

Registration

N4506L

Category

Airplane

Engines

1

Operator

USDA/Forest Service

Operating rule

Public Use

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Dublin → Dublin

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

NYC03TA138

Nobody was injured.

A compressor turbine blade fracture which resulted in a power loss, and forced landing. Factor were the rocks in the landing area, and the operator's decision to operate the engine beyond the engine manufacturer's recommendations for overhaul.

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

Read the full NTSB narrative

The Air Tractor was spreading chemical when the pilot observed orange flames and black smoke emitting from the engine exhausts. The engine lost power, he feathered the propeller, and set up for a forced landing in a nearby open field. The airplane touched down, rolled a short distance, and struck embedded rock. The landing gear collapsed, the fuselage was wrinkled, and the propeller separated from the engine. Examination of the PWC PT6A-20 engine revealed several compressor turbine blades had fractured and been released into the engine gas path. The blades also impacted adjacent and downstream components. The compressor turbine blades used in the engine were not approved by PWC; however, they were PMA manufactured with FAA approval. Since engine overhaul, the engine had accumulated 10,978.8 hours and 15,059 cycles. According to the FAA, the PWC recommended overhaul time of 3,600 hours. The airplane was being operated on a USDA Forest Service contact that required the engine to have been overhauled within the manufacturer's specifications. The engine's time since overhaul was not discovered by the Forest Service when they accepted the airplane for use on their contract.

Quoted verbatim from the NTSB record.