Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Santa Margarita, California 93453
Saturday, August 24, 1991 11:25 PDT
NTSB Narrative Summary Released at Completion of Accident
THE CERTIFICATED PRIVATE PILOT AND A PASSENGER WERE CONDUCTING A FLIGHT TEST OF AN UNREGISTERED, HOMEBUILT AIRPLANE. THE AIRPLANE WAS BEING MARKETED AS AN ULTRALIGHT VEHICLE WITH AN EXCEPTION OF THE ULTRALIGHT REGULATIONS GRANTED TO THE EXPERIMENTAL AIRCRAFT ASSOCIATION. THE PILOT WAS PERFORMING AEROBATIC MANEUVERS WHILE THE PASSENGER WAS FILMING THE EVENT FROM THE REAR SEAT. DURING THE PULL-UP PORTION OF AN IMMELMAN MANEUVER, THE LEFT WING FAILED AND FOLDED UPWARDS. THE PILOT DEPLOYED A BALLISTIC PARACHUTE TO CONTROL THE AIRPLNE'S DESCENT. AS THE PARACHUTE DEPLOYED, IT BECAME ENTANGLED WITH THE ENGINE PROPELLER AND WAS DAMAGED AND ONLY PARTIALLY INFLATED. THE AIRPLANE DESCENDED AND STRUCK THE GROUND AT ABOUT 50 MPH. THE AIRPLANE AND PILOT DID NOT QUALIFY FOR THE CONDITIONS OF THE ULTRALIGHT REGULATION EXEMPTION, AND THE VEHICLE IS CONSIDERED TO BE AN AIRPLANE.
NTSB Probable Cause Narrative
THE FAILURE OF THE WING SPAR WHEN THE DESIGN LIMITS OF THE AIRPLANE WAS EXCEEDED BY THE PILOT. CONTRIBUTING TO THE ACCIDENT WAS AN INADEQUATE AIRFRAME DESIGN AND AN ABRUPT MOVEMENT OF THE FLIGHT CONTROLS BY THE PILOT.
Event Information
| Type of Event | Accident |
| Event Date | 8/24/1991 |
| Event Day of the Week | Saturday |
| Time of Event | 1125 |
| Event Time Zone | Pacific Daylight Time |
| Event City | SANTA MARGARITA |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93453 |
| Event Date Year | 1991 |
| Event Date Month | 8 |
| 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 | 0 |
| Degrees magnetic from airport | 0 |
| Airport Elevation | -- |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Pilot |
| Time of the weather observation | 0 |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | |
| Elevation of weather observation facility | 0 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | |
| 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) | 38 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | 0 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 0 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | Serious |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | 1 |
| Injury Total None | -- |
| Injury Total Serious | 1 |
| Injury Total All | 2 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 2247 |
| NTSB Notification Source | -- |
| NTSB Notification Date | -- |
| NTSB Notification Time | 0 |
| Fiche Number and/or location -used to find docket information | 45762 |
| Date of most recent change to record | Oct 31 2002 4:06PM |
| User who most recently changed record | NTSB\ZUZL |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | NONE |
| NTSB Number | LAX91LA375 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Destroyed |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BEIERLE |
| Aircraft Model | THUNDER GULL J |
| Aircraft Series Identifier | THUNDER GU |
| Aircraft Serial Number | 1 |
| Certified Max Gross Weight | 800 |
| Aircraft Category | Ultralight |
| Aircraft Registration Class | Not Registered |
| 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 | Unknown |
| Date of Last Inspection | Jan 2 2000 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 41 |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | |
| Aircraft Owner Street Address | |
| Aircraft Owner City | |
| Aircraft Owner State | |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | |
| Operator is an individual? | -- |
| Operator Name | MARK BEIERLE |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | STAR ROUTE 313 |
| Operator City | SANTA MARGARITA |
| Operator State | CA |
| Operator Country | |
| Operator Zip code | 93453 |
| Operator Code | |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| 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) | Unknown |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | NONE |
| Departure City | SANTA MARGARITA |
| Departure State | CA |
| Departure Country | |
| Departure Time | 1115 |
| Departure Time Zone | PDT |
| 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 | Maneuvering |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 26 2001 3:54PM |
| 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 | -- |