Sukhoi SU-31 accident near Immokalee, Florida, February 20, 1996
On February 20, 1996 at about 4:43 pm local time, a Sukhoi SU-31, registered N31MX, was destroyed in an accident near Immokalee, Florida (Immokalee airport). It was a flight of an unrecorded kind under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
the manufacturer's improper composite curing process, which resulted in wing spar voids and subsequent failure of the wing during aerobatic flight.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 20, 1996 · about 4:43 pm local time
- Place
- Immokalee, Florida · Immokalee
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Sukhoi SU-31 · all SU-31s on the register
- Registration
- N31MX · no longer on the register · serial 03-03
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 16,000 hours in all; 10 in this make and model; 10 in the last 30 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 11 hours
- Last inspection: annual inspection, February 15, 1996; 11 hours since
- Maximum gross weight: 2,425 lb
- Seats: 1
- Landing gear: fixed
- Engine: Voronezh M-14P (piston); 0 hours total
- Fire on the ground
The flight
- Flight plan: none
- Runway 0, 5,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 180° at 12 knots
- Visibility: 7 statute miles
- Sky: scat at 2,400 ft
- Temperature: 79°F (26°C), dew point 63°F (17°C)
- Altimeter: 30.00 inHg
- Observation at 4:46 pm from APF, 30 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Other NTSB records under N31MX the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ATL96FA051.