Air Tractor AT-401 N4545W

Summary

On 19 August 2005 at about 16:00 local time, a Air Tractor AT-401 registered N4545W was involved in an incident near Winnie, Texas, United States. One person was on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 August 2005 at 16:00

Classification

Incident

Location

Winnie, Texas, United States

Nearest airport

Winnie/Stowell Airport (T90)

Coordinates

29.8022, -94.4253

Aircraft

Air Tractor AT-401

Registration

N4545W

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Positioning

Phase of flight

Not recorded

Route

Winnie → Wharton

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

DFW05IA222

Nobody was injured.

The loss of engine power due to the failure of the second-stage turbine wheel as a result of low cycle fatigue.

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

Read the full NTSB narrative

The 18,950-hour commercial pilot reported that that shortly after departure the "engine blew" and he executed a forced landing to a field, and the airplane received minor damage. Examination of the turbine engine revealed that it had experienced an uncontained separation of the second-stage turbine disk as a result of low cycle fatigue. No evidence of deep scratches or gouges were observed on the bore surface or on the forward and aft face of the disk. A review of maintenance records revealed that the engine had been previously installed on an aircraft that was registered in a foreign country, and the maintenance records were not complete. When the operator purchased this engine, he informed the facility that performed his engine maintenance that the second-stage turbine rotor was installed on the engine in 1992 with a total of 730 cycles. The maintenance facility then produced a new life-limit card for the second stage turbine disk. Based on this data, the disk had accrued a total of approximately 1,738 cycles at the time it failed. The rotor had an FAA approved life-limit of 5,400 cycles. However, according to the production records from the manufacturer of the engine, the second-stage turbine rotor had originally been shipped with zero hours and cycles in another, new production engine on January 24, 1973, making the part 33 years old.

Quoted verbatim from the NTSB record.