# Accident 20000422005369A: Airtrc AT502A, Queen Creek, AZ, April 22, 2000 - Type: FAA accident report (Accident/Incident Data System), as reported - Date: April 22, 2000, 10:19 local time - Place: Queen Creek, AZ - Damage: Destroyed - Phase of flight: Low Level Operations - Operating rules: Agricultural (Part 137) - Operator: ZCOG - Location: 33.2487° N, 111.6343° W: Placed by OpenAirDocs: center of Queen Creek, AZ, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=33.2487&lon=-111.6343&mi=10 - Aircraft: N15466, a cancelled registration (https://openairdocs.org/deregistered/N15466-2017-07-17) (OpenAirDocs) - Registry model: Air Tractor AT-502A (registry code 0390306, https://openairdocs.org/model/air-tractor-at-502a) (OpenAirDocs) - Registry engine: Pratt & Whitney PT6A series (registry code 52032, https://openairdocs.org/engine/pratt-whitney-pt6a-series) (OpenAirDocs) - Reported make and model: AIRTRC AT502A - Reported engine: PWA PT6A45A - People aboard: 1 - Fatal injuries: 1 - Pilot flight hours: 26,190 total - NTSB investigation: [NTSB LAX00FA169](https://openairdocs.org/ntsb/LAX00FA169) (OpenAirDocs) - FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/) - Page: https://openairdocs.org/incident/20000422005369A ## Narrative As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^. (-23) ON APRIL 22, 2000, AT 1019 HOURS MOUNTAIN STANDARD TIME, AIR TRACTOR AT-502A, N15466, PILOTED BY JOE CLIFTON HENDERSON SUFFERED AN IN-FLIGHT SEPARATION OF THE LEFT WING DURING AERIAL APPLICATION. THE AIRCRAFT WAS IN A LEVEL PASS OVER A CROP FIELD LOCATED AT ELLSWORTH AND GERMANN ROADS, WHEN THE LEFT WING SEPARATED CAUSING THE AIRCRAFT TO ROLL TO THE LEFT AND IMPAC THE GROUND INVERTED. THE PILOT SUFFERED FATAL INJURIES ON IMPACT. THE LEFT WING WAS FOUND APPROXIMATELY 300 FEET FROM THE MAIN FUSELAGE WRECKAGE. GROUND WITNESSES REPORTED NO UNUSUAL MANEUVERS PRIOR TO THE WING FAILURE. (.4) THE AIRPLANE WAS SPRAYING CHEMICALS ON A FIELD OF CROPS WHEN THE LEFT WING SEPARATED IN FLIGHT. GROUND WITNESSES SAID THAT THE AIRPLANE WAS MAKING A LEVEL SPRAY PASS OVER A POTATO CROP WHEN THE LEFT WING FAILED. NO UNUSUAL METEOROLOGICAL PHENOMENA WERE OBSERVED IN THE AREA, AND THE AIRPLANE DID NOT PERFORM ANY UNUSUAL MANEUVERS PRIOR TO THE FAILURE. THE LEFT WING'S LOWER SPAR CAP WAS FOUND TO HAVE FRACTURED IN FATIGUE AT A POINT THAT TRANSECTED THE INBOARD ATTACH BLOCK BOLT HOLE WHERE THE SPAR ATTACHES TO THE CENTER SECTION SPAR CARRY THROUGH MEMBER. MULTIPLE ORIGIN SITES WERE IDENTIFIED WITHIN THE BOLT HOLE BORE, WITH CORROSION PITTING EVIDENT AT THE ORIGIN POINTS. THE SPAR CAPS MET THE HARDNESS, CHEMISTRY, AND MICROSTRUCTURE OF THE PRODUCTION DRAWING SPECIFIED MATERIAL. AIR TRACTOR SERVICE LETTER 118 AND THE MAINTENANCE MANUAL SPECIFY AN INSPECTION PROCEDURE, WHICH CALLS FOR THE REMOVAL OF THE HOPPER FOR A DETAILED INSPECTION OF THE SPAR CAPS FOR CRACKS; ONE AREA IDENTIFIED AS CRITICAL FOR CRACKING WAS THE INBOARD BOLT HOLE BORE. THE INSPECTION INTERVAL WAS SPECIFIED AS EVERY 2,000 HOURS OR 3 YEARS. THE NUMBER OF CRACK ARREST STRIATIONS IN THE FATIGUE REGION WAS DETERMINED FROM THE FIRST POINT THE CRACK WOULD BE VISIBLE FROM BENEATH THE ATTACH BLOCK DURING THE SPECIFIED INSPECTION, AND THE MEAN TIME FOR THE FATIGUE CRACK TO PROGRESS FROM DETECTIBLE DURING THE INSPECTION TO FAILURE WAS CALCULATED TO BE ABOUT 105 HOURS. EXAMINATION OF THE RIGHT WING LOWER SPAR CAP REVEALED THE PRESENCE OF MULTIPLE FATIGUE CRACKS EMANATING FROM CORROSION PITS WITHIN THE OUTBOARD BOLT HOLE BORE. NO MAINTENANCE RECORDS WERE LOCATED FOR EITHER THE AIRFRAME OR ENGINE. A MECHANIC WAS LOCATED WHO PERFORMED SOME PERIODIC MAINTENANCE ON THE AIRCRAFT. HE STATED THAT DURING THE REMOVAL OF THEHOPPER IN MAY 1997, 2 YEARS 11 MONTHS PRIOR TO THE ACCIDENT, HE HAD ACCOMPLISHED THE 2,000-HOUR CHECK OF THE WING SPARS IN THE AREA OF THE ATTACH BOLTS AS REQUIRED BY SERVICE LETTER 118. BASED ON OTHER RECORDS, THE AIRCRAFT WAS BELIEVED TO HAVE FLOWN AN AVERAGE OF 500 HOURS PER YEAR AND WOULD HAVE ACCUMULATED ONLY 1,500 HOURS SINCE THE INSPECTION. ## The NTSB's investigation of this event (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB LAX00FA169](https://openairdocs.org/ntsb/LAX00FA169), Apr 22, 2000: Air Tractor 502A (N15466), Queen Creek, AZ, destroyed, 1 fatal. Probable cause: The fatigue failure and in-flight separation of the left wing due to the manufacturer's underestimation during the aircraft design process of the time interval from fatigue crack initiation to… From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.