Individually Owned: 150,657
Corporate Owned: 137,281
Caldwell Airport
Aircraft Accident/Incident Report
Greenleaf, Idaho 83626
Monday, September 19, 2011 13:15 MDT
NTSB Narrative Summary Released at Completion of Accident
The pilot was performing aerobatic maneuvers in the plans-built experimental biplane. He successfully completed an aerobatic routine and then elected to perform it a second time. During the initial dive, as he began to level the airplane, he observed the outboard trailing edge of the upper left wing fail, with fabric material in trail from the aft spar. He regained partial control, but decided to bail out a short time later. The airplane subsequently rolled inverted and entered a near-vertical descent that continued to ground impact.
The 15-year-old airplane, which was purchased by the pilot 16 months before the accident, had fabric-covered wooden wings. The pilot described the build quality of the airplane as "average" and stated that he had noted chips and cracks in the paint, which were acceptable when referenced to the inspection criteria in the fabric manufacturer’s installation manual.
The airplane sustained extensive impact damage, and sections of the upper left wing separated from the airframe in flight and were not located. Fabric material from the recovered wreckage was examined, and the paint was cracked, fragmented, and separated from the majority of the fabric surface. It appeared that the fabric had been incorrectly treated prior to painting and then painted with a brittle automotive paint, which was prone to cracking. The fabric manufacturer’s installation manual cautioned that automotive paint can lead to premature failure of fabric cover because cracking can expose the fabric material to damaging ultraviolet light, which will substantially reduce the fabric's strength. The failed area was on the upper wing, which would have been exposed to sunlight on a regular basis. Although the improperly treated and painted fabric may have led to the in-flight failure of the upper left wing, a determination of the wing’s failure mode could not be made because the separated section of the wing was not recovered.
NTSB Probable Cause Narrative
Structural failure of the upper left wing during aerobatic flight.
Event Information
| Type of Event | Accident |
| Event Date | 9/19/2011 |
| Event Day of the Week | Monday |
| Time of Event | 1315 |
| Event Time Zone | Mountain Daylight Time |
| Event City | Greenleaf |
| Event State | IDAHO |
| Event Country | -- |
| Zipcode of the event site | 83626 |
| Event Date Year | 2011 |
| Event Date Month | 9 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 433929n |
| Event Location Longitude | 1165017w |
| Event Location Airport | Caldwell |
| Event Location Nearest Airport ID | EUL |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 10 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 2432 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Pilot |
| Time of the weather observation | 1255 Mountain Daylight Time |
| Direction of event from weather observation facility (degrees) | 90 |
| Weather Observation Facility ID | EUL |
| Elevation of weather observation facility | 2432 |
| Distance of event from weather observation facility (units?) | 9 |
| Time Zone of the weather observation | MDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 24 |
| Dew Point at event time (in degress fahrenheit) | 7 |
| Wind Direction (degrees magnetic) | 330 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 5 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.11 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 30028 |
| NTSB Notification Source | NWM ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Aug 2 2012 4:11PM |
| User who most recently changed record | snyg |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N77VW |
| NTSB Number | WPR11LA459 |
| Missing Aircraft Indicator | -- |
| 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 | MCARTHUR |
| Aircraft Model | STEEN SKYBOLT |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 1 |
| Certified Max Gross Weight | 1800 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | Yes |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Conditional |
| Date of Last Inspection | Sep 3 2011 12:00AM |
| Airframe hours since last inspection | 4 |
| Airframe Hours | 320 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | C91-A |
| Aircraft Owner Name | BENNETT STEVEN MICHAEL |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | BOISE |
| Aircraft Owner State | ID |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 83709-8559 |
| Operator is an individual? | Yes |
| Operator Name | BENNETT STEVEN MICHAEL |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | BOISE |
| Operator State | ID |
| Operator Country | USA |
| Operator Zip code | 83709-8559 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| 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) | Personal |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | EUL |
| Departure City | Caldwell |
| Departure State | ID |
| Departure Country | USA |
| Departure Time | 1255 |
| Departure Time Zone | MDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | EUL |
| Destination City | Caldwell |
| Destination State | ID |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jun 25 2012 4:48PM |
| User who most recently changed record | coos |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |