Sauber believes it has identified and solved the DRS malfunction that caused Marcus Ericsson's dramatic accident in Friday's FP2 session.
Ericsson's DRS failed to close as he approached Monza's first chicane, pitching the Sauber left into the barriers and into a series rolls, leaving the C37 in a pitiful state but its driver fortunately uninjured.
Initial analysis of team mate Charles Leclerc's rear wing assembly revealed a similar Drag Reduction System issue which the team partly resolved before the Monegasque resumed work in the afternoon's free practice session.
"It was very tricky, we would arrive at the end of the straight and didn't know if it would close or not," explained Leclerc.
"I had the same issue but I've been luckier with it, it closed a bit earlier than Marcus. We found the issue, we resolved it, but that required a bit of sacrifice in performance.
"We know what to do tomorrow to not have this problem and have full performance."
Before heading back out on track, Leclerc was informed that he could manually close the DRS as his team sought to reassure him that the device would work properly. The Sauber driver duly complete his session, clocking in with the ninth fastest time.
"I have full trust in my guys and I know they were doing their job," he said.
"If they tell me it will be fine the next run then it will be. We found the issue and we ended the day on a high."
According to Sauber team boss Fred Vasseur, the cause of Ericsson's failure was rooted in a slight design flaw of the team's Monza-spec low-downforce rear wing.
"This is the first time [this problem has happened] and probably due to the developed downforce for today," he said. "It is a new rear wing, but it is not the wing, just the DRS flap."
While his massive 20G crash obviously left him a bit shaken, Marcus Ericsson was given a clean bill of health by the FIA. He'll also be given a new C37 chassis for the remainder of the race weekend, with Sauber personnel breaking the overnight curfew to build up the Sweede's new car.
"Marcus is okay," said Vasseur said. "We had a chat together after the session.
"He was disappointed to miss the rest of the practice session, and also a bit shocked, but the car will be ready to race."
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