Accident Sukhoi Su-31 N31MX,
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ASN Wikibase Occurrence # 39135
 
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Date:Tuesday 20 February 1996
Time:12:43 LT
Type:Silhouette image of generic SU31 model; specific model in this crash may look slightly different    
Sukhoi Su-31
Owner/operator:Richard V. Massegee
Registration: N31MX
MSN: 03-03
Total airframe hrs:11 hours
Engine model:Voronezh M-14P
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Destroyed
Category:Accident
Location:Immokalee, FL -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Unknown
Departure airport:
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
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.

Probable Cause: the manufacturer's improper composite curing process, which resulted in wing spar voids and subsequent failure of the wing during aerobatic flight.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: ATL96FA051
Status: Investigation completed
Duration: 7 months
Download report: Final report

Sources:

NTSB ATL96FA051

Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
09-Apr-2024 08:10 ASN Update Bot Updated [Time, Operator, Other fatalities, Source, Narrative, Accident report]

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