CHI91DCD01

Factual narrative

THE PLT WAS PARTICIPATING IN A PYLON AIR RACE FOR FORMULA V RACERS. ABT HALF WAY THRU THE RACE, AS HE WAS MNVRG PAST THE #2 PYLON, THE LEFT WING BGN TO SEPARATE. THE WING THEN FOLDED OVR THE TOP OF THE ACFT. THE WING & PIECES OF THE CANOPY FELL TO THE GND. AS THE WING SEPD, THE ACFT BGN A VIOLENT ROLL & FLWD A TRAJECTORY PATH TO THE GND. INV REVEALED THE INNER PORTION OF EACH WING WAS DESIGNED WITH BOX SPAR CONSTRUCTION, SECURED TO A FUSELAGE CARRY-THRU CONFIGURATION. THE OUTER WING SPARS CONSISTED OF A SERIES OF UPPER & LOWER STRAPS. THESE WERE SECURED TO A SHEET METAL WEB WITH RIVETS. THE 4 LOWER SPAR STRAPS HAD FAILED; 2 HAD FAILED AT THE 1ST RIVET HOLE OUTBOARD OF THE BOX SPAR CONFIGURATION; ONE FAILED AT THE 1ST BOLT HOLE NEAR THE OUTBOARD END OF THE BOX SPAR & THE 4TH FAILED FLUSH WITH THE OUTBOARD END OF THE BOX SPAR. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12