Mercedes director of trackside engineering Andrew Shovlin has explained the issue during George Russell's pit-stop that left the Briton struggling for grip at the Emilia Romagna Grand Prix.
Russell finished a stellar fourth from 11th on the grid after making the most of the first corner meleé triggered by Daniel Ricciardo and Carlos Sainz to ensure he kept his record of being the only driver to have finished in the top five in each of the opening four races.
The former Williams driver was making advances towards Lando Norris but when pitting to change from intermediates to slicks as the track dried, Mercedes failed to get the desired tweaks to the front wing needed to alter the set-up.
This left Russell severely lacking front-end grip, resulting in understeer for the majority of the race and putting him firmly in the clutches of a charging Valtteri Bottas.
Whilst he was able to fend off the Alfa Romeo, Russell was unable to close on Norris to threaten for a second successive podium.
Detailing the issue that cost Russell, Shovlin said: “When we make an adjustment at a pit stop we actually use an electronic gun that can put a pre-programmed number of turns in there.
"We have to do that because the stops have gotten so quick you can no longer make a manual adjustment where the mechanics on the front wing would count the number of turns.
"We have a gun that does this and we can programme how many turns we want it to do and it will deliver that.
"The issue we had with this particular stop was actually that both guns had got knocked as they went in on the front wing endplate, the front-wing endplates on these cars are much bigger and that had caused the gun to reset."
Insisting the issue had never happened before, Shovlin added: "So, it wasn’t so much that anything had broken.
"It was really one of those issues that was a feature of the changes that we have made on the car, it hadn’t occurred to us before in practice sessions where we are trying pit stops or pit stop practice itself.
"But that was why we didn’t actually get any adjust on George's stop and the upshot was that we had to drive the entire stint with that much lower flap angle that we would normally run in the wet.”
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