Dario Franchitti was quickest in the opening IndyCar practice session at Sonoma's Infineon Raceway that was interrupted by a violent accident involving Nelson Philippe, Will Power and EJ Viso.
Both Power and Philippe were taken to a nearby hospital for their injuries to be assessed after the crash, which happened when Philippe spun out of Turn 3a and was collected by following cars.
In his first race back with Conquest Racing, Philippe spun twice at the same blind crest in the early part of the session, and the second rotation left his car stationery on the racing line.
Viso was able to jink in avoidance, but his HVM Dallara's left rear wheel still struck the front of Philippe's car. Power then appeared on the scene moments later and hit the side of Philippe's Dallara with substantial force. The Australian Penske driver has been taken to Santa Rosa Memorial Hospital by helicopter for back pain to be investigated, while Philippe is being transported by road having sustained a foot injury. Both also suffered concussion, but were reported to be awake and alert in the track's medical center.
The accident halted the session for half an hour, although 10 minutes of running were added at the end of the morning. Ganassi driver Franchitti went fastest late on, beating Penske's Helio Castroneves and star rookie Mike Conway (Dreyer & Reinbold), who had briefly been quickest of all in the closing stages.
Hideki Mutoh was among the frontrunners throughout and ended up fourth in the best of the Andretti Green cars, ahead of championship leader Scott Dixon (Ganassi).
Graham Rahal completed the top six for Newman/Haas/Lanigan, but his teammate Oriol Servia only completed four laps before stopping with a fuel pump problem.
Other drivers in trouble included Ryan Briscoe, who spun his Penske Dallara-Honda early on, Dan Wheldon (Panther), who crashed at the Turn 9/10 chicane just as the Viso, Power and Philippe incident unfolded, and Tony Kanaan, whose AGR car developed a brake problem. Ed Carpenter (Vision) also caused a yellow with a high-speed spin through the dirt.
Franck Montagny impressed by taking eighth place on his series debut (bar the IRL-officiated Champ Car finale in Long Beach last year). The Frenchman is having a one-off outing in a fifth AGR entry.