Yuki Tsunoda was one of several drivers who faced a post-qualifying investigation for potential yellow flag infringements in Q1 at the Singapore Grand Prix.
Pierre Gasly caused a yellow flag in the final seconds of Q1 when he suffered a technical problem in his Alpine and came to a stop partly down a small escape road to the left on the entry to the tight Turn 11-12 sequence.
Several drivers - Tsunoda, George Russell, Sauber pair Nico Hulkenberg and Gabriel Bortoleto, and Lance Stroll - were placed under investigation for an alleged infringement.
Stroll, who was not even on a push lap when he went past Gasly’s car, was cleared immediately, while the others were shifted to being investigated after qualifying - although Russell was then cleared while Q2 was still going on.
That is likely because his circumstances were different to the other drivers’.
Russell was the first car to arrive at Turn 11 after Gasly stopped and it appears from his onboard camera there was just one yellow flag being waved on the left-hand side.
While there was a single-waved yellow there, and Russell was quicker in that mini-sector, the caution had not been registered on the race control system and the marshal’s post is significantly obscured.
It is essentially blind to the drivers as it is obscured by a wall that juts out slightly, and is positioned on the left and right at the turn-in point for when the track quickly goes right - the direction the drivers are looking.
The situation was slightly different for Tsunoda, as the extra time before he reached Turn 11 meant he was warned of the single yellow by his race engineer and the large flag signal panel was illuminated and flashing yellow on the right hand side as well.
Tsunoda lifted slightly and was slower in that mini-sector even though his overall lap was an improvement and launched him from the drop zone to 10th.
That got the Red Bull driver into Q2 but he was slowest in the second segment anyway.
As for Hulkenberg, he was warned of the single yellow by his engineer too, and his mini-sectors in that part of the lap were also slower.
Both Saubers were in the Q1 dropzone at the time and Hulkenberg was able to improve enough over the rest of his lap to jump to 13th.
Hulkenberg nearly made it all the way to Q3, as he ended Q2 11th. Bortoleto, though, was eliminated from Q1 in 16th - his middle sector, which includes the area Gasly stopped, was 0.02s slower than Hulkenberg’s.
All three were cleared after qualifying, as the telemetry data "clearly showed" their speed was legal.
