A system quirk was the main factor behind Yuki Tsunoda being unable to unlap himself in the Formula 1 Brazilian Grand Prix, the FIA have announced.
After marshals were unable to retrieve the stricken McLaren of Lando Norris under a Virtual Safety Car period, it was upgraded to the full Safety Car to allow a crane to move the car after a suspected hydraulics failure.
Three cars were lapped at the time: Yuki Tsunoda and the Williams duo of Alex Albon and Nicholas Latifi.
When time came to allow these cars to unlap themselves, only cars #23 and #6 were waved through by race control with Tsunoda not following suit as the #22 had not been given permission due to the new automated systems believing he had already unlapped himself.
On the restart, Tsunoda pulled over to the pit-wall as the race went green to allow the front-runners to battle for position, having rejoined from the pit-lane sandwiched between Carlos Sainz Jr and Charles Leclerc.
However, the quirk meant he could not improve on his 17th place, which is where he finished - the only car one lap behind race winner George Russell.
After the race, the FIA revealed that a system loophole unique to the Interlagos was the root cause of the situation.
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"All of the systems functioned correctly and according to the regulations," a FIA spokesperson told media, including RacingNews365.com.
"The unusual situation arose as a result of the idiosyncrasies of the specific circuit and scenario."
Below are the series of events which led to the confusion:
- Tsunoda was the first to cross Safety Car line one following the deployment of the Safety Car
- On the following lap, he became the first car to cross the SC1 line for a second time which would normally trigger the systems to indicate he is eligible to unlap himself.
- However, Tsunoda then entered the pit-lane, and as he was able to go faster than those cars who stayed out, he unlapped himself by crossing the control line in the pitlane.
- As intended, the systems then showed he was one lap down again after he rejoined and the snake behind the Safety Car had filtered by.
- However, as he had unlapped himself once, he was not eligible to do so when the Safety Car was called in.
- Race Control then made a check with the timekeepers, who confirmed only Latifi and Albon were able to unlap themselves.
The FIA admitted the case was a "very unusual scenario" but were clear that "no system or procedural errors" were made.
"It is one of those unpredictable scenarios that can happen no immediate changes are needed to be implemented," the statement continued.
"This will of course be discussed at future Sporting Advisory Committees as part of the normal review procedures."
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