Mercedes continued their disastrous start to pre-season when Lewis Hamilton crashed his car nose-first into a tyre wall after suffering brake problems on his first day of testing.
The 2008 world champion's car careered straight across the gravel run-off at the Jerez circuit's turn six, the notorious Dry Sack corner where Michael Schumacher and Jacques Villeneuve collided in the 1997 title-deciding European Grand Prix.
The car's wheel tracks indicated Hamilton, who stepped out unhurt after staying in the car for a few minutes, had been a mere passenger with no response from the car's steering as it slid off.
"Lewis suffered a loss of rear brake pressure, the front brakes enabled him to slow the car but he couldn't avoid the barrier," Mercedes said.
"We have traced the problem to the hydraulic brake line connecting to the right-rear caliper," the team added.
The British-based team had a difficult start to the first pre-season test on Tuesday when Germany's Nico Rosberg completed only 14 laps before his car burst into flames after a wiring problem.