MONACO — Australian Daniel Ricciardo set the pace for Red Bull in Monaco Grand Prix practice Thursday, with crashes and a loose drain cover putting safety back in the spotlight at Formula One's showcase race.
Ricciardo lapped the twisty harbourside circuit in a quickest time of one minute 14.607 seconds, 0.606 faster than triple champion Lewis Hamilton in the closest Mercedes with championship leader Nico Rosberg third.
"Come qualifying and race day Mercedes will turn it up but hopefully I can stay in front," said the Australian.
Hamilton was fastest in the morning with a lap of 1:15.537 on the new ultrasoft Pirelli tires making their debut this week.
The Briton, who collided with Rosberg in Spain 11 days ago and lags the German by 43 points after five races, is seeking to end his team mate's run of three successive Monaco wins but Ricciardo could be a threat to both.
"Generally it's been a really positive start. We've got everything we needed done in both sessions and our pace looks good, so hopefully that continues through the rest of the weekend," said Hamilton.
Red Bull had targeted Monaco as its best chance of victory this season, before Dutch teenager Max Verstappen won in Spain on his debut for the team.
Ricciardo has a new specification Renault engine for Sunday's race, which Verstappen will not get until the next race in Canada due to a shortage of parts.
"The engine has helped a little bit but obviously we have a good car around here as well, I think it's down to a little bit of both," said Ricciardo of his time.
Verstappen was fifth and fourth in the respective sessions.
Ferrari's Sebastian Vettel, who spun at Mirabeau and hit the barrier after lunch, had been third fastest in the morning but four tenths slower than Hamilton.
With the paddock rocked by news that the family of the late French driver Jules Bianchi were taking legal action against Formula One, his former Marussia team and the governing FIA after his death last year, safety was a talking point.
A series of crashes led to the virtual safety car being deployed three times in the morning before the session was stopped when a loose drain cover damaged Rosberg's car and Jenson Button's McLaren. Photographs showed a sizeable piece of metal had been dislodged, fortunately without consequences for Button or anyone following behind.
Track workers were deployed to Sainte Devote to weld down the offending cover.
"That was an incident we definitely don't want to see again around here," Button said.
Brazilian Felipe Massa, who was hit on the head and seriously injured by bouncing debris at the 2009 Hungarian Grand Prix, crashed out earlier when he skewed his Williams into the barriers at the first Sainte Devote corner.
Mexican Esteban Gutierrez stopped his Haas before Portier with electrical problems, and Renault's British rookie Jolyon Palmer crashed at Tabac.
"Sorry guys," Palmer, whose Danish teammate Kevin Magnussen also crashed in the afternoon, said over the radio.
Indonesian rookie Rio Haryanto crashed his Manor in the second session at the tunnel exit.
Bianchi family plans legal action against F1
The family of the late French Formula One driver Jules Bianchi are planning legal action against the sport's governing body, his former Marussia team and Bernie Ecclestone's Formula One Group, they said in a statement Thursday.
"We seek justice for Jules, and want to establish the truth about the decisions that led to our son's crash at the Japanese Grand Prix in 2014," his father Philippe said in the statement issued by British firm Stewarts Law.
"As a family, we have so many unanswered questions and feel that Jules' accident and death could have been avoided if a series of mistakes had not been made."
Bianchi, 25, died in hospital in his home town of Nice last July after suffering serious head injuries when he crashed into a recovery crane at Suzuka during the October 2014 race.
He was the first Formula One driver to die of injuries sustained during a race since Brazilian triple world champion Ayrton Senna in 1994.
There was no immediate response from the FIA, whose report into the accident said that the Frenchman had not slowed sufficiently under warning flags before crashing.
The report found Bianchi's car hit the tractor at 126 kph and said medical services were not at fault in their handling of the aftermath.
