Not sure what's happening but I've had this problem every now and then where I just suddenly start losing altitude and then I get this rpm warning, if I take my collective to the maximum my shkval even turns off for some reason, but when I drop it, it turns back on.

It's possible that I lost a rotor blade somehow although I wasn't attacked this time so I don't see how I could have lost one rotor blade, I don't think it's the self created vortex thing I've heard mention of. I tried putting my nose down to go forward out of the vortex but I still end up with the rpm warning and eventually lose all my altitude.

Your screenshot tells me that you've lost Engine #1, explaining why you are gracefully falling from the sky. What is does not tell me is why. I would hazard a guess from the snow falling outside that your anti-ice systems have not been toggled on (4 switches) on overhead panel IIRC.

I can't see, but I am guessing temps are pretty cold? That would explain those little white flakes. Turn on engine intake de-icing or fall out of the sky.

INU heat on always
Pitot(s) heat on in winter or wet weather.
Rotor blade heat on in winter
Engine intake heat on in winter.

"Rotor icing" EKRAN message means conditions are ripe for icing. It will sound if you have heat on or off. If you see the message more than once and do not turn on de-icing, better go land as it is too late.

ooh.. Im sorry Viper told you this!

Aha! Thank you, I will try this today.

What these guys are saying is true. The reason your Skhval shuts off during all this is because it's powered by the generators, which are driven by the transmission. If you lose an engine, or try to pull more blade pitch from the rotors than the engines can keep up with, your rotor RPMs will drop triggering your zebra-striped warning light and audio. If you allow the RPMs to continue to bleed off the generators will drop offline, and you'll lose all gen-powered systems.

Remember when the RPM needle reaches the lower red line on the gauge, that's all the lift you're gonna get from the blades. Pulling any more collective will only make things worse. Another thing that can affect how much lift is required to maintain level flight is airspeed. An airspeed of around 120-130kmh will give you the least amount of total drag on the rotor system, giving you the best climb rate; or, in a situation where you're power limited, the best power margin for maintaining level flight.

Another way you can induce losing your RPMs and Gens is by having a low collective setting, and then aggressively pull in a high collective setting. This causes the rotors to instantly increase the blade pitch and drag, and the engines don't have time to spool up to maintain rotor RPM's. Sometimes I'll decelerate so aggressively that the nose will be high, the collective will be bottomed out, and when the airspeed starts dropping below 50kmh or so, I drop the nose and slam in collective to maintain altitude, and my rotor RPM's drop through the floor due to the combination of all that. Falling starts, vortex ring state follows that, and it usually ends badly.

You said it much more eloquently then I could have, Raptor.

Honestly I had forgotten exactly why it happens, I just knew it happens.