LAX98LA129 · Ayres S2RT-34RE
Ayres S2RT-34RE · Accident: total loss of engine power (mechanical failure) en route
From Buckeye Municipal Airport (BXK) to an unrecorded destination
Event
- NTSB case
- LAX98LA129
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Ayres S2RT-34RE
- Aircraft type
- Ayres S2
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N4010X
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Buckeye Municipal Airport (BXK), Buckeye, AZTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Other maintenance personnel › Maintenance, overhaul, improper
- Turbine assembly, turbine blade › Fatigue
- Turbine assembly, turbine blade › Incorrect
- Turbine assembly, turbine blade › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
An Ayres S2R airplane lost power and crashed following a landing attempt to a field. The subsequent disassembly of the engine revealed that the compressor turbine disk was intact, but that all of the CT blades were fractured across the airfoils adjacent to the blade root platform. The Canadian Transportation Safety Board's engineering branch found that there were 55 blades of one part number and 3 blades of another part number which were not authorized for use in a PT6A-34AG engine. The three unapproved blades had a different heat code than was approved for this engine. One of the unapproved blades revealed a fatigue fracture on the surface as seen by the scanning electron microscope. The blades were manufactured by Doncaster, under a FAA Parts Manufacturing Approval as an alternate part for PWC CT blades. They were then packaged and shipped to Superior Air Parts. Superior Air parts would repackage the blades in Superior Air parts packaging prior to reshipping the blades. Doncaster's stated that Superior was the sole distributor of the Doncaster blades. Both the quality control standards at Superior Air Parts and Air Force Turbine Services did not notice the three incorrect CT blades, which were shipped from Superior Air Parts and subsequently, installed on the engine. Additionally, when the engine underwent repair work and these blades were installed, the new CT blades were installed and the radial tip clearance between the blades and segments was 0.0025 inches less than the minimum required by the PT6 engine manual.
Probable cause
The incorrect turbine blades installed on the engine, the fractured compressor turbine blades and separation of the blade, and the improper maintenance installation of the incorrect CT blades by the repair station. A factor in the accident was the inadequate quality control procedures by both the shipper of the CT blades and the maintenance facility which installed the blades.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX98LA129
- Event ID
- 20001211X09725
- Case number
- LAX98LA129
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1998-03-25.
- API snapshot SHA-256: ba0185055de0bda2d3f5eb80f4c638e29d893b5b8054d96bc3d32242329cc1a2; retrieved 2026-09-22T17:56:23.372Z.