Individually Owned: 150,657
Corporate Owned: 137,281
Rigby-Jefferson County Airport
Aircraft Accident/Incident Report
Rigby, Idaho 83442
Tuesady, August 20, 2002 6:52 MDT
NTSB Narrative Summary Released at Completion of Accident
The pilot of the Air Tractor AT-502B had reported observing no abnormalities during engine start and the subsequent application of power during takeoff. Climbing through 100 feet he heard a loud "bang," observed sparks and flames exiting the engine exhaust ports and transitioned to a power off forced landing. As the aircraft was rolling out it encountered a ditch and the main landing gear separated. Post-crash examination of the engine revealed extensive damage to the blades of the compressor turbine disk and erosive burning damage to the vanes of the vane ring situated immediately upstream of the compressor turbine disk. The 22 year old Pratt & Whitney PT6A-34 turboshaft engine had a total of 7,070 hours since new and had undergone an undocumented overhaul 5,820 hours previously to the accident. The last hot section inspection referenced in the engine log occurred 2,871 hours previous to the accident and the last logged inspection was a 100-hour inspection 324 hours and eight months previous to the accident.
NTSB Probable Cause Narrative
The failure of one or more compressor turbine blades resulting in a shutdown of the engine during initial climb resulting in a forced landing. Contributing factors were the eroded condition of the compressor turbine guide vane nozzles and the ditch which the aircraft encountered during the landing rollout.
Event Information
| Type of Event | Accident |
| Event Date | 8/20/2002 |
| Event Day of the Week | Tuesday |
| Time of Event | 652 |
| Event Time Zone | Mountain Daylight Time |
| Event City | Rigby |
| Event State | IDAHO |
| Event Country | -- |
| Zipcode of the event site | 83442 |
| Event Date Year | 2002 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 433800N |
| Event Location Longitude | 1115500W |
| Event Location Airport | Rigby-Jefferson County |
| Event Location Nearest Airport ID | U56 |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | 180 |
| Airport Elevation | 4845 |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 653 Mountain Daylight Time |
| Direction of event from weather observation facility (degrees) | 207 |
| Weather Observation Facility ID | IDA |
| Elevation of weather observation facility | 4740 |
| Distance of event from weather observation facility (units?) | 10 |
| Time Zone of the weather observation | MDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 14000 |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 16 |
| Dew Point at event time (in degress fahrenheit) | 1 |
| Wind Direction (degrees magnetic) | 190 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 14 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.82 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 1 |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 13636 |
| NTSB Notification Source | FAA SEA ROC |
| NTSB Notification Date | Aug 20 2002 12:00AM |
| NTSB Notification Time | 703 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Jul 1 2003 9:44AM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | SLC FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N6146G |
| NTSB Number | SEA02LA161 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 137: Agricultural |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Air Tractor |
| Aircraft Model | AT-502B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 502B-0299 |
| Certified Max Gross Weight | 9700 |
| 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 | 100 Hour |
| Date of Last Inspection | Dec 20 2001 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | -- |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Queen Bee Air Specialties, Inc. |
| Aircraft Owner Street Address | 136 North Yellowstone |
| Aircraft Owner City | Rigby |
| Aircraft Owner State | ID |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 83442 |
| Operator is an individual? | No |
| 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 | JRFG |
| Owner has at least one certificate | -- |
| Other Operator of large aircraft? | -- |
| 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) | Aerial Application |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | U56 |
| Departure City | Rigby |
| Departure State | ID |
| Departure Country | USA |
| Departure Time | 650 |
| Departure Time Zone | MDT |
| 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 | Takeoff - initial climb |
| Report sent to ICAO? | Yes |
| Evacuation occurred | No |
| Date of most recent change to record | May 2 2003 4:40PM |
| User who most recently changed record | STAM |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 19 |
| Runway Length | 3500 |
| Runway Width | 50 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |