I don't often post on this part of the forum but wanted to share my thoughts as it seems like a lot of people are pointing fingers at the marshals, stewards and Charlie. It's getting close to 20 years since I competed in motorsport, and that wasn't in single seaters, so forgive me if my opinions are out of date or incorrect. I've also pasted part of this post from an answer I gave elsewhere to non motorsport fans so sorry if I sound like I'm over explaining.
Like a few others seem to have done, I saw the clip when it was auto-played on facebook. If I'm honest, I would probably have watched anyway simply because the descriptions of the accidents turn into chinese whispers and gossip, and I like to understand what happened. That said it was horrific. I agree with the person who said it reminded them of the Pryce accident at Kylami, although for force of impact it also reminded me of the Jeff Krosnoff accident at Toronto. It was a horrific.
At the start of the clip Adrian Sutil's car is on the other side of the marshall's post and they are correctly displaying double waved yellows which means that the drivers should not only slow down but also be prepared to stop immediately in case of danger. As the tractor reverses back to the other side of the marshal's post then the marshal's were technically correct to be waving the green flag. The double-waved yellows should also have been waved by marshals on the track side all the way back to the previous marshal's post (and I believe they were). The green flags begin immediately after the danger site according to track position.
That's the theory and to be fair to the marshal's they are not supposed to deviate from that theory. It does highlight some problems though. In my opinion, the height and prominence of the marshal's post in relation to the track-side marshalls meant that the drivers' attention may have been caught by the green flag before they had passed all of the double waved yellows, especially taking into account the increasing spray as the rain had started to increase just before this. The authorities need to look at what the procedure should be for green flags at a post so close to the danger area, on a bend, even though the post was technically after the obstruction. I think they need to look at having a small buffer zone past the accident as well as before it (depending on where on the track it occurs).
An even bigger concern is that drivers simply ignore double waved yellows too often and treat them as single yellow flags. I don't want to criticise any single driver because they are all guilty. Unless the danger is in the middle of the track then drivers do not slow down enough to be at the point where they can stop immediately if required. The fact it was raining should be irrelevant in some ways, as the drivers should take this into account for stopping distances in the same way they do for slowing down for corners. The drivers have failed to do this for so long that nobody seems to expect them to lift more than a fraction - to the point where they are only losing fractions of a second when passing an accident.
Because this is known to be the case then the race director should probably have sent the safety car out before releasing the tractor to recover Sutil's car. In his defence, the track conditions had not long started to get worse due to increasing rain and the accident took place during the time that he would normally have been getting data and feedback on how bad track conditions were.
In my opinion, the bottom line is that it was a 'perfect storm' of unlucky events that combined to both cause the accident and highlight some deficiencies in the laid down procedure. I hope they can look at it and learn, without throwing blame around and looking for scapegoats.
As well as being an unlucky series of events it was also an extremely lucky outcome of the accident. I can't believe Bianchi wasn't killed instantly, and that no marshalls were wiped out (including the one in between the tractor and the tyre wall when the tractor was thrown up and backwards). Let's just hope Bianchi pulls through and fully recovers. Thoughts with his friends and family.
Going forward, F1 needs to find a way of eliminating as much danger as possible without making every race a safety car procession. My suggestion would be that instead of deploying the safety car at every accident they could employ a system where the cars had to travel on the limiter from the last straight section a safe distance before the accident to the first green flag after the accident. The technology already exists and is already fitted to the cars. The change in marshaling procedure would be no greater than the change that came in when safety cars were introduced. This would decrease the speed at which the cars passed the accident, and wouldn't involve the safety car travelling flat out to set the pace (a danger in itself). It would also create a much quicker way of sanitising the danger area rather than waiting for cars to catch the safety car. I know the drivers have to conform to delta times, but a limiter takes it out of their hands. As well as increasing safety in the danger area, it also allows racing to continue on the rest of the circuit. Just an idea...