NTSB Identification: DFW08LA223
14 CFR Part 137: Agricultural
Accident occurred Monday, September 01, 2008 in Uvalde, TX
Probable Cause Approval Date: 05/06/2010
Aircraft: ROCKWELL INTERNATIONAL S-2R, registration: N8472V
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The engine of the agricultural airplane lost power while it was maneuvering at low altitude. The airplane impacted thick vegetation and terrain, causing substantial damage to the right wing, nose and tail. A subsequent teardown examination of the engine showed little evidence that the engine was operating at the time of impact, but the ingestion of vegetation into the combustor and the torsional failure of the torsion shaft suggests that there was some rotation of the engine at the time of impact. The engine examination also revealed that several turbine rotors had damage and missing blade material due to short term operation of the engine at an over temperature condition. There was evidence that the rotors had been operating for several hours after the over temperature event that caused the stress rupture of the blades. Further, the examination showed that the first stage turbine rotor and the prop pitch control cam did not conform to Honeywell specifications and were not authorized replacement parts, and a previous weld repair on the engine combustor plenum did not conform to standard practices for weld repairs on aerospace parts.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A total loss of engine power due to the improper use of unauthorized replacement parts in the engine and repeated operation of the engine in an over-temperature condition.

Full narrative available

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