Flight Hydro. Iso. Switch by landing gear handle

[Baz000]

Just wondering when this switch should be actuated after take-off in the F-14 because or even if it should be. From my understanding, this switch stops pumping hydro fluid to your brakes, NWS and landing gear, I read in the NATOPS that this switch should not be actuated immediately after retraction of the landing gear because of the gear locks. Apparently if you are too bushy tailed with it, you can potentially cause the landing gear struts to rest onto the gear doors and cause an unintended lowering of the landing gear. So this begs the question, when do you actuate this switch... What phase of flight?

 

I Figure this switch would be important to help you with hydro leaks or battle damage, considering it would mean less systems unnecessary to actual flight having hydro fluid being routed to them. Also figure it would let the Bi-Di pump work better since you shunted off hydro fluid to unnecessary systems except for landing / stopping.

 

In theory, by taking away more demand from the hydraulic system you should have more supply available in case of an emergency with the system where the Bi-Di has to kick in, right? Giving you longer time to use your flight controls vs. without using the flight isolation switch for the hydraulic system?

[Sideburns]

The bi-direction pump will basically flow pressure from COMBined-FLighT hydraulic systems or vice versa in the event one systems pressure is not being replenished, i.e. an engine out situation. In the event of a suspected leak you definitely want to shut off the bi-directional pump to isolate each hydraulics circuit and preserve what you can / figure out the situation (this is modelled, if you disabled the bi-di pump and shut an engine off you will notice the pressure drop eventually if you keep moving things, flight surfaces, wing sweep or cycle landing gear. Eventually the affected circuit loses enough pressure to be ineffective and things stop working).

 

Not sure what purpose this gear hydro isolation servers, perhaps it is a maintenance or additional battle damage control function? If you do end up in an leak situation it is probably best to flick "Hydro Iso" and the bi-direction pump off for maximal anti-leak protection, the manual indicates it comes back on automatically with gear down lever so what have you got to lose.

[Victory205]

...

...I Figure this switch would be important to help you with hydro leaks or battle damage, considering it would mean less systems unnecessary to actual flight having hydro fluid being routed to them. Also figure it would let the Bi-Di pump work better since you shunted off hydro fluid to unnecessary systems except for landing / stopping...

 

 

Leave the switch alone unless the PCL directs you to actuate it in the event of a hydraulic leak. You are correct in that it isolates the system to prevent battle damage from losing all fluids in the combined system.

 

When the gear handle is moved to the down position, a physical lever moves the switch to the normal position.

 

In reality, the bi-directional pump is there to provide hydraulic power to the opposite system in case of engine failures. Every hydraulic failure I ever had, resulted in the loss of fluid, meaning the bi-di or "PTU" in the airliners, didn't salvage the opposite system.

 

The pilot could also inadvertently flip that switch when raising the gear after a violent cat shot at night, causing the gear to fail to retract, whereupon a wingman stated that "the gear pins were in, with two foot long red flags flying in the airstream", which is virtually impossible on a cat shot since about 80 people look at the jet before a carrier launch, thereby causing the pilot to dump fuel, recover and have the flight deck Chief say, "what are you doing back here?". "Well, my test pilot Pax River bad assed wingman said that the gear pins were in!" "No they weren't, everything was fine"... Oh, thinking carefully, "Guess I must have hit the switch...but we have a real problem because my Phd genius wingman is still up there flying around, unable to see because he is blind"

 

I heard that happened once...

 

[Sideburns]

Also as a further clarification most missions and servers will probably not have random failures enabled, unlike real life. Therefore the main reason you are likely to have hydraulic fluid loss in the game is battle damage rather than a system failure or defect.

 

@Victory205 Great story as ever :)

[Cocker]

So, in case of battle damage and hydraulic loss on one of the circuit, best way to prevent total hydraulic loss would be to turn the hydraulic transfer pump off, then switching the hydraulic isolation switch to flight?

[Sideburns]

So, in case of battle damage and hydraulic loss on one of the circuit, best way to prevent total hydraulic loss would be to turn the hydraulic transfer pump off, then switching the hydraulic isolation switch to flight?

 

It's explained nicely in the HB manual, at http://www.heatblur.se/F-14Manual/ge...draulic-system . One slight omission on my part, the bi-direction hydraulic pump will auto shut off if one system goes below 500psi so there is a degree of protection there. I have had battle damage in the F14, from lower end IR missiles and aaa, that has resulted in hydraulic damage so it is useful to know how the system works. This also assumes that it was not both hydraulic circuits that were damaged, otherwise you will "bleed out" eventually anyway and then be dependent on the emergency flight hydraulic pump, where it is handy to know this has two speeds. Automatically it goes to low but it also has a high mode. The high mode is a limited time option but does give better response on the surfaces, handy for the landing phase of your flight home.

 

You can setup the mission editor to simulate some failures to practice, or as I mentioned before manually use the isolation switch and shut down an engine to simulate each of the circuits losing its pump.