With BAR announcing a long-term deal with engine partner Honda just before the session, Briton Davidson went out and blasted round the Hockenheim circuit in one minute 15.756 seconds.

That was 0.108 of a second quicker than Schumacher, chasing a record-equalling 11th win in 12 starts on Sunday in a home race that could also seal Ferrari's sixth successive constructors' championship.

Davidson completed 32 laps before parking up on the grass run-off with four minutes to go.

Finland's Kimi Raikkonen confirmed McLaren's considerable progress since their nightmare start to the season with the third fastest time.

Brazilian Ricardo Zonta, another Friday test driver, was fourth fastest in a heavily-revised Toyota.

His compatriot Antonio Pizzonia, making a Formula One comeback with Williams as a stand-in for injured German Ralf Schumacher after being dropped by Jaguar last year, clocked the 10th fastest time.

That was well on the pace of his Colombian team mate Juan Pablo Montoya, last year's runaway winner from pole position, in ninth place and just 0.050 quicker.

Mark Webber, Pizzonia's former Jaguar team mate, was the only driver who failed to set a time.

A team spokeswoman said the Australian had been due to do a few laps towards the end of the session but that proved impossible after Austrian team mate Christian Klien's car developed a problem.

The same part was changed on Webber's car as a precaution, leaving no time to get out on track.

German Timo Glock, the Jordan test driver, caused the session to be halted briefly with 18 minutes remaining when he shattered his Jordan's front wing on a kerb and littered the track with carbon-fibre debris.