Button forgives mechanic's Monaco error

Button retired on the third lap of the showcase race 12 days ago after his engine overheated because a bung had been left in the car's sidepod when he left the pits, limiting the inflow of air.

"I'm sure the person who did make the mistake will never, ever do that again," said Button at the Turkish Grand Prix.

"The guy was devastated, and in a way I felt sorry for him because we all make mistakes, and it wasn't just a mistake, it was miscommunication more than anything else.

"That bung shouldn't have been there in the first place. He wasn't looking to take it out because it wasn't supposed to be there," added Button.

"When you know you have to take it out, you take it out, but when you don't think it's there, and it is, it's a difficult one."

Button said the two had found each other when he was visiting the factory in Woking last week and talked things through.

McLaren dominated free practice yesterday with Lewis Hamilton quickest in the morning and Button lapping even faster after lunch. Last year's winner with Brawn at the undulating anti-clockwise Istanbul Park circuit, Button set the pace in the afternoon with a time of one minute 28.280 seconds.

That time was faster than Sebastian Vettel's 2009 pole position for Red Bull of 1:28.316, but Button felt the Red Bulls still looked the most menacing.

"The car feels reasonably good around here," said Button.

"There are still some areas where we're not so strong and the Red Bulls will once again be the cars to beat in qualifying. We can't get away from that. I just hope we're closer than we've been in the last two races."

Red Bull's championship leader Mark Webber was second in the afternoon, but stopped on track five minutes from the end with a smoking car.

The Australian said the engine was a high mileage one that had been used before and was coming to the end of its life, so the failure was no surprise. Vettel, fifth in the morning, was third with the team experimenting with a version of the 'F-duct' that McLaren have pioneered to reduce drag on the straight.

Yesterday was the German's first chance to try out a different chassis, used previously only in pre-season testing, at a grand prix weekend after a defect was discovered in the car he had used for the past six races.

"We still need to do some fine-tuning but it looks good," he said. "I think McLaren looks very competitive here, their system seems to be working well and they seem quite a bit quicker than everyone else on the straights."

Friday practice is more morale-boosting than indicative of true performance, although Webber had warned on Thursday the McLarens could be a real threat after Hamilton had been close to their pace in Spain.

"But we're also mindful of the fact that Ferrari, and also if Mercedes have a clean weekend, there's lots of guys that can come towards us, so we're definitely not taking anything for granted," he added.

Webber is going for a third win in a row after his victories in Spain and Monaco.

"We need to analyse the new F-duct system tonight, we know it's not the most straightforward of systems," said the Australian. "Whether we race it or not, we don't know yet."

Ferrari's Fernando Alonso, third in the championship ahead of his team's 800th race, was ninth and fifth respectively.

Force India's German Adrian Sutil had the only accident of the morning session, the German losing control through the difficult Turn Eight and spinning into the barriers.