James Allison has confirmed that the pit-stop errors that lost Mercedes the Sakhir Grand Prix were caused by a team radio issue.
George Russell and Valtteri Bottas were comfortably running in P1 and P2 when the team called them both in to pit under the Safety Car.
It proved to be a disastrous call as a mix-up of the tyres meant that Russell had to pit again a lap later, while Bottas ended up stuck on the old set he came in on.
Allison, the German team’s technical director, has now explained exactly what went wrong.
“I think you have to start by understanding that the radios that the pit crew use can only hear one voice at a time,” he said on the Mercedes YouTube channel.
“Although they are listening to more than one potential input source, they can only hear one input source at a time… and they are normally listening to their boss on the pit wall, Ron Meadows, who will tell them when they need to come out into the pit lane in order to do a tyre stop.
“But their radios are not just tuned in to Ron Meadows. They are also tuned in or they are scanning to listen to the driver. So, on George’s side of the garage, his mechanics have their radios scanning, listening out for the driver.
“Right at the point where Ron was calling to the pit crew to do the double stack, George was also speaking on the radio and for half of the people on George’s side of the garage, instead of hearing what Ron was saying, the radio had latched onto what George was saying instead.
“So, half of the guys on George’s side of the garage did not hear the message and that meant that when everyone came out into the pitlane, only half of George’s tyres arrived and when George actually showed up in the pitlane to get his stop done, the tyres that were sitting there were half his and half Valtteri’s because the full set of Valtteri’s did arrive.
“So, one tiny mistake, programming the radios in a way that they could override hearing this really important call from Ronnie Meadows on the pit wall is what caused all that mess.”
Even after the mistake, Russell, on fresh tyres, still had a chance of winning his race, and quickly began to make his way through the order, climbing up to P2.
However, more disaster struck when he then picked up a puncture and had to pit yet again.
While Allison isn’t certain of what caused said puncture, he believes it was either debris on the track or the driver’s use of the kerbs.
“Well, we don’t know for sure, all we can tell you is that there was debris on the track as a result of Aitken’s crash,” he added.
“Maybe he picked up a small shard of carbon splinter from that incident and we also know that in getting past all the people that he was overtaking, he was having to take some fairly aggressive lines over kerbs in order to muscle his way by.
“It is possible that either from the debris of Aitken’s incident or from the kerb riding he was doing that he picked up a cut that caused the puncture.”