Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Buckeye, Arizona 85326
Tuesady, March 24, 1998 18:45 MST
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Accident |
| Event Date | 3/24/1998 |
| Event Day of the Week | Tuesday |
| Time of Event | 1845 |
| Event Time Zone | Mountain Standard Time |
| Event City | BUCKEYE |
| Event State | ARIZONA |
| Event Country | -- |
| Zipcode of the event site | 85326 |
| Event Date Year | 1998 |
| Event Date Month | 3 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | |
| Event Location Nearest Airport ID | |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1745 Mountain Standard Time |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | KGY |
| Elevation of weather observation facility | 959 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | MST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 20 |
| Air Temperature at event time (in degrees celsius) | -5 |
| Dew Point at event time (in degress fahrenheit) | 32 |
| Wind Direction (degrees magnetic) | 90 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 1435 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Mar 25 1998 12:00AM |
| NTSB Notification Time | 945 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Feb 23 2001 1:56PM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N4010X |
| NTSB Number | LAX98LA129 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Ayres |
| Aircraft Model | S2RT-34RE |
| Aircraft Series Identifier | S2RT-34RE |
| Aircraft Serial Number | 6024 |
| Certified Max Gross Weight | 6000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 1 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Mar 14 1998 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 9708 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | PIERCE AVIATION |
| Aircraft Owner Street Address | P. O. BOX 607 |
| Aircraft Owner City | BUCKEYE |
| Aircraft Owner State | AZ |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 85326 |
| Operator is an individual? | -- |
| Operator Name | |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | |
| Operator City | |
| Operator State | |
| Operator Country | |
| Operator Zip code | |
| Operator Code | |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Agriculture |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Positioning |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | BXK |
| Departure City | BUCKEYE |
| Departure State | AZ |
| Departure Country | |
| Departure Time | 1645 |
| Departure Time Zone | MST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Feb 23 2001 1:56PM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |