To never isolate the hydraulic system once the switch is recycled. He says it might come back on so leave it on. Do you guys have similar experience?

Id love for that system to kick back on. Hyd off flight is scary. 

Ever hear of a RFD?

excuse me--RFM

Troll.  But i'll play.  Thats exactly why you turn it off and leave it off because it might come back on at a really bad time and make a minor event into a big event.

When you are about to touch down and are fighting the controls, is a BAD time to have the hydrauics come on.

Let's use the Bell 206 system for an example. Most hydraulic failures are the result of a leak. The system is high pressure (400psi?) and low volume (Less than a quartish?) so it doesn't take long for the system to fail after a leak. When you turn the switch off you are re-routing the hydraulic fluid, really a mist now, from the actuators back to the reservoir. That is a much smaller volume of space for the fluid to occupy and the pump is still being driven by the transmission. So, it is possible that a significant amount of fluid could become pressurized from the pump to the reservoir. If you were to turn the Hydraulic switch back on that fluid will go to one or more of the actuators applying boost in a short and probably asymmetrical manor. That could cause a loss of control.

This is not a Land ASAP emergency as the flight controls are working the same, they just require more force to move. You could conceivably fly until you fan out of gas. I would error on the side of caution though and land promptly because that pump could be running dry and getting hot with a lot of flammable fluid sprayed who knows where and plenty of wind to fan the flames if they do ignite. The pump's drive shaft is necked down between the transmission and the pump so it should break there if the pump seizes.

The AS-350 was harder to fly boost off because it is heavier and has more blades. After some accidents after extended boost off flight AEC changed their EP to disallow that. I hired a guy once that had failed out of Temsco's training because he couldn't fly for the extended period they thought was necessary for their Glacier tours. I thought "I can teach this guy!". Wrong, it was beyond some smaller pilot's physical ability.

The heaviest single system I ever flew was the H-55. When my instructor first turned the boost off I was seriously wondering how I was going to get that fat b*stard on the ground! But, slowing down, setting a landing attitude, and rolling on above ETL proved to be no big deal.

Not a pilot, but I remember a war at Era over landing an A-Star on a platform with no hydraulics. The company wanted pilots to do a run-on, pilots thought differently from what I recall.

You guys are so judgemental. Just saying the RFM doesn't need to be the be all end all of how to handle emergencies. 

in this case it certainly is

a dual hydraulics failure IMC in a BH212.  Yes, there is a way to deal with it.  Just remember when you put the collective down you absolutely will not get it back up!  Fly the ILS as well.

What caused the dual failure? I thought the systems were totally isolated from each other. 

lets be serious 

dual hydraulic failure in imc is about as likely as the pilot that thinks the radios are broken because nobody is answering him at three in the morning 

Agree, but some of these young uns never seen a 212 up close much less fly one. 

Had 3, all Bells and lived.  So depends on the aircraft.

Had 3, all Bells and lived.  So depends on the aircraft.

you survived to tell the tale of a hydraulic failure in a 206 3 times. impressive.

in a UH1H in an LZ.  Flew it out, didn't want to stick around.  Not fun.

are those with curiousity and professionalism who just want to know, then there are those who play the probabilities with lives.  Choose ur poison, wisely.

they are.  But, never say never, realistically.

Is it me or do helicopter pilots just keep getting dumber

might have a point, but, the dual hydraulics failure in a 212 has occurred.  Knowing how to deal with it is very important, but, gotta be a professional pilot first, no doubt.