NHRA announces preliminary findings of investigation into Phoenix fatal accident
NHRA released today the preliminary findings of its investigation regarding the incident in Phoenix which took the life of a spectator, and announced the implementation of precautionary measures in response.
Immediately after the Feb. 21 incident, in which a wheel became detached from Antron Brown's Top Fuel dragster and struck and killed a female spectator, NHRA's Technical Department launched an investigation with the aid of series teams, and manufacturers. The sanctioning body's investigation was aided by Dr. Juan Herrera, who holds a Ph.D. in Mechanical Engineering. Some of his specialties include metallurgical engineering, failure analysis, vehicle dynamics and accident reconstruction. Dr. Herrera worked closely with the Don Schumacher Racing team as well as with the NHRA Tech Department.
It appears that very quickly after the car launched, it experienced the loss of the No. 5 cylinder, severe tire shake, and rapidly decreasing acceleration forces. The left wheel then slipped slightly on the hub. The wheel studs experienced a bending force and then failure, which resulted in the wheel becoming detached from the hub. The studs themselves had some slight but pre-existing cracking that likely was not detectable upon visual examination. After the left tire/wheel assembly came off, the car arced to the left and the tire/wheel assembly struck the left side of the car. This strike changed the wheel's forward direction of travel and diverted it to the left, where it went off the left side of the track, and tragically struck the spectator.
Immediately after the Phoenix incident, manufacturers responded by analyzing, inspecting and servicing as necessary their respective parts. Certain technical changes have been made in some cases. As a precautionary measure, the type of stud involved in the Phoenix incident will no longer be in use. At the race in Gainesville, NHRA inspected certain aspects of Top Fuel and Funny Car wheels, hubs and studs and will continue to spot check vehicles.
Preliminary testing conducted by teams of two new wheel retention device designs was conducted on the Monday following the NHRA Tire Kingdom Gatornationals at Gainesville Raceway. The wheel retention systems are intended to improve retention of the wheel to the race vehicle. NHRA will allow Top Fuel and Funny Car teams who choose to do so to use either of the two designs that were tested beginning at the NHRA Four-Wide Nationals at ZMax Dragway in Charlotte.
The NHRA says it will continue to work with the teams and manufacturers as they develop and test these two designs, as well as others that are in the preliminary design and testing stage.