SUZUKA, Japan (Reuters) - Williams were fined 60,000 euros ($81,100) on Friday after a wheel came off Pastor Maldonado's car during Japanese Grand Prix practice.
Formula One stewards said in a statement that the incident, in which the rear left wheel bounced across the track, was regarded as a serious safety issue.
"Examination of the parts concerned revealed that the wheel fastener had not been completely fastened, thus not engaging the first retaining plunger," they added.
"The secondary retaining plunger failed to keep the wheel in place."
Formula One introduced a secondary retainer mechanism after a television cameraman was hit by a wheel that came off Australian Mark Webber's Red Bull during a German Grand Prix pitstop in July and bounced down the pit lane.
($1 = 0.7395 euros)
(Reporting by Alan Baldwin, editing by Ed Osmond)