Air Tractor 400 N73080

Summary

On 21 October 1996 at about 15:30 local time, a Air Tractor 400 registered N73080, operated by Patterson Air Farming, was involved in an accident near Sylvester, Georgia, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

21 October 1996 at 15:30

Classification

Accident

Location

Sylvester, Georgia, United States

Coordinates

31.5205, -83.8301

Aircraft

Air Tractor 400

Registration

N73080

Category

Airplane

Engines

1

Operator

Patterson Air Farming

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

MIA97LA012

1 person had minor injuries.

Was the pilots intentional disregard for operating the engine contrary to the flight manuals for intentionally exceeding the maximum engine temperature, resulting in creep failure of one of the compressor turbine blades.

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

Read the full NTSB narrative

The pilot intentionally operated the engine exceeding the maximum temperature limits during aerial application flights which he was advised against by several different individuals. The pilot stated that during an aerial application flight he first heard a loud sound with a subsequent loss of engine power. He initiated a forced landing in a field and after touchdown with the brakes heavily applied to avoid obstructions ahead, the airplane nosed over. Examination of the engine revealed that 7 of the 58 compressor turbine blades were failed near the midspan or platform. Oxidation was detected at one of the 7 blades and creep and necking was detected at the trailing edge of another of the blades. Additionally, severe burn erosion was noted to the trailing edges of the compressor turbine guide vanes. According to the ASM Metals Handbook, creep is a time dependent strain occurring under stress. Additionally, at elevated temperature, the service life of a metal component subjected to either non-vibratory or vibratory loading is predictably limited.

Quoted verbatim from the NTSB record.