Jordan's start-line problems continued yesterday as Heinz-Harald Frentzen stopped on track when the teams were given the opportunity to test their launch control systems on the Monaco grid.

The Irish team admitted on Wednesday that they would abandon the system at this weekend's grand prix in favour of driver-controlled starts as the Monaco pit exit was too dangerous an area to conduct simulations.

But yesterday, in light of concerns expressed about launch control failures in the wake of the four start-line failures in Austria, the teams were given permission to practice starts on the grid at the end of each of yesterday's free practice sessions.

Jordan seized the chance, but once again Frentzen was left stranded as electronic problems dropped his idle speed too low, cutting the car out as he stopped on the grid.

While not strictly a launch control problem, the failure will again make the team think twice about leaving their race starts to electronics rather than their drivers.

Yesterday, both drivers performed without fault, Frentzen taking seventh quickest time, while Jarno Trulli claimed fifth, aided in part by a radical new aerodynamic package tested in Valencia last week.

The modifications saw Trulli's EJ11 sporting a radical mid-wing design involving a two-foot high T-shaped wing mounted in front of the driver in the middle of the body. This extreme pursuit of the extra downforce needed on Monaco's slippery streets harks back to the x-wings run by the team in 1997. Those additions were subsequently banned on safety grounds and yesterday it suffered the same fate.

Following yesterday's practice sessions the FIA's technical delegate ruled that the wing constituted a "dangerous construction" and told the team that the car would be excluded if the device was used again.

Trulli seemed to benefit from the wing as he climbed to fifth, also running in race configuration, but later admitted that his EJ11 wasn't all it could be.

"The car's balance isn't as good as I'd like at the moment and we still have a lot of work to do, particularly with the tyres," he said.

"Our race configuration seems pretty competitive though, but we'll have to look at the data to see what alterations we need to make for Saturday as qualifying is so important here."

The day's top spots predictably went to Ferrari and McLaren, but the surprise was that it was Mika Hakkinen rather than championship contender David Coulthard in the quickest McLaren.

The Finn posted the day's fastest time, some four tenths ahead of second-placed Michael Schumacher. Coulthard, meanwhile, was back in sixth, dropping down the places when he was sidelined after a minor accident.

Schumacher's progress, by contrast, was characteristically trouble-free as he went within half a second of Hakkinen.

The differential, however, was of little concern to the German, Schumacher admitted that he had been concentrating on set-up for the race rather than the qualifying trim many others were working towards.

"We concentrated on working for the race, as usual, working on tyres and set-up," he said. "At this track, more than any other, the times on the first day mean very little, not just because you don't know what fuel loads the others are using, but also because traffic's a big problem here."

Third-placed Ralf Schumacher was the only close rival ahead of the Jordans yesterday, but both he and Williams team-mate Juan Pablo Montoya suffered big accidents late in the afternoon.

Meanwhile, Trulli has been elected as one of the three directors of the Grand Prix Drivers' Association. He will work alongside existing directors David Coulthard and Michael Schumacher.

The association was originally founded in 1961 at Monte Carlo's Hotel Metropole by a group including Jack Brabham, Jim Clark, Stirling Moss, Graham Hill and Bruce McLaren.

The group was re-established in 1994 in the wake of the deaths of Ayrton Senna and Roland Ratzenberger and works closely with the FIA mainly on safety issues.