Individually Owned: 150,657
Corporate Owned: 137,281
Immokalee Airport
Aircraft Accident/Incident Report
Immokalee, Florida 33934
Tuesady, February 20, 1996 11:43 EST
NTSB Narrative Summary Released at Completion of Accident
The pilot was conducting a practice aerobatic flight, with two aerobatic pilots critiquing him from the ground. About ten minutes into the flight, the pilot initiated a pull toward the vertical with about 360 km/hr and 7 Gs, according to witnesses. This would have been well within the maximum airspeed and load specifications of 450 km/hr and 10 Gs, respectively. The right wing of the airplane separated during the pull up. The airplane entered a right roll and an uncontrolled descent, then it collided with the ground about 1 mile north of the airport. According to witnesses, the engine was developing power until impact, and the pilot did not announce any malfunctions or problems, prior to the wing failure. A postcrash ground fire consumed the fuselage. The unburned right wing was found about 3/4 mile east of the main wreckage. Testing of the wing spar was performed by the NTSB and MAK (Russian Investigative Authorities). Both agencies found numerous voids in the composite spar caps. The investigation revealed evidence that the curing process for the wing spar did not provide adequate vacuum pressure. There was evidence that during the curing process, the fibers separated from each other, which resulted in voids in the final composite material.
NTSB Probable Cause Narrative
the manufacturer's improper composite curing process, which resulted in wing spar voids and subsequent failure of the wing during aerobatic flight.
Event Information
| Type of Event | Accident |
| Event Date | 2/20/1996 |
| Event Day of the Week | Tuesday |
| Time of Event | 1143 |
| Event Time Zone | Eastern Standard Time |
| Event City | IMMOKALEE |
| Event State | FLORIDA |
| Event Country | -- |
| Zipcode of the event site | 33934 |
| Event Date Year | 1996 |
| Event Date Month | 2 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | IMMOKALEE |
| Event Location Nearest Airport ID | IMM |
| 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 | 360 |
| Airport Elevation | 37 |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1146 Eastern Standard Time |
| Direction of event from weather observation facility (degrees) | 225 |
| Weather Observation Facility ID | APF |
| Elevation of weather observation facility | 9 |
| Distance of event from weather observation facility (units?) | 30 |
| Time Zone of the weather observation | EST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 2400 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 7 |
| Air Temperature at event time (in degrees celsius) | 26 |
| Dew Point at event time (in degress fahrenheit) | 17 |
| Wind Direction (degrees magnetic) | 180 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 12 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 30 |
| Density Altitude (feet) | 1100 |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | Fatal |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | 1 |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 445 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Feb 20 1996 12:00AM |
| NTSB Notification Time | 1301 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 8 2000 9:50AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N31MX |
| NTSB Number | ATL96FA051 |
| 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 | Ground |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Sukhoi |
| Aircraft Model | SU-31 |
| Aircraft Series Identifier | SU-31 |
| Aircraft Serial Number | 03-03 |
| Certified Max Gross Weight | 2425 |
| 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 | Feb 15 1996 12:00AM |
| Airframe hours since last inspection | 11 |
| Airframe Hours | 11 |
| ELT Installed | Yes |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | RICHARD V. MASSEGEE |
| Aircraft Owner Street Address | 173 EL CAMINO CAMPO |
| Aircraft Owner City | CORRALES |
| Aircraft Owner State | NM |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 87008 |
| 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 | 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 | Yes |
| Departure Airport Code | |
| Departure City | |
| Departure State | |
| Departure Country | |
| Departure Time | 0 |
| Departure Time Zone | |
| 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 2 2001 10:34AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | 5000 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |