EICAS FUEL- Explaned?

[Kyle Sanders]

I just posted about a fuel problem.

I wanted to put this in with it but i thought it would be considered a different topic as a whole.

In the manual you have a VERY graphical description of the PFD of the CRJ-200.

But not the EICAS FUEL page.

There are a few things on this page that does not make much sense to me.

A graphical description of "what is what" on that page would be VERY much appreciated.

Thanks again

[Japo32]

Have you read the complete manual? because it is explained in the Main Manual, page 87.

[Kyle Sanders]

Yes, i have read the entire manual. I am sorry that i did not go back and research more.

I thank you for this.

But i still want to know what the valves that are directly below the xFlow Pumps Valves (item #3)?

Also, The square that has a temperature indicated there, what is that?

Thanks again!

[Av8n4life]

OK. I'll answer your last questions first. I'm not sure how this is simulated in the JRollon CRJ but here's how it works in the actual airplane:

The valves below the XFLOW/APU pump (the vales under the #3s) are the transfer valves. There are two ways these valves are actuated: automatically or manually. In Automatic mode, the computer monitors the balance between the wing tanks. When it senses an imbalance of 200 pounds or greater between the two wing tanks, the XFLOW/APU pump will activate and the transfer valve on the low side will open. The XFLOW/APU pump draws fuel from BOTH wing tanks and deposits it back in the low tank...yes, some fuel just makes a big "loop" from itself back to itself, it's not the most efficient system out there. It will stop when the lower tank is over-balanced by 50 pounds. In manual mode (when you press the XFlow Auto Override switch on the overhead panel), you can open those transfer valves manually, but there is no balance logic provided by the computer.

The squares that have temperatures in them simply indicate the temperature of the fuel just before it enters the engines. This fuel is warmed by a fuel/oil heat exchanger (i.e. fuel cools the engine oil, engine oil heats the fuel). In the real aircraft there is a bulk fuel temperature sensor as well, which would be in the left tank area of the synoptic. That measures the temperature of the fuel in the tanks.

From the top of the synoptic:

Total Fuel: Self-explanatory.

2: Gravity XFLOW valve--this is kind of a "no-touchy" button, as you found out in your other thread. We only use this in the airplane in extraordinary situations, and it is correct that we can sideslip the aircraft to better effect fuel transfer using this method. Just remember, though, things have to be going REALLY rough generally for you to use that switch.

3. Transfer valves. See above.

Just below the transfer valves are the transfer ejectors. The "megaphones" you see on the synoptic are the ejectors. An ejector is something like a fuel pump, but it has no moving parts--it's only "powered" by motive flow from the engine-driven fuel pumps.

Basically what's happening is this. If you have your CRJ full of fuel (which almost never happens in real life), the aircraft is going to want to get rid of the center tank fuel first. The transfer ejectors make this happen...they take fuel out of the center tank and put it in the wing tanks. Once it gets into the wing tanks, the scavenge ejectors (the "megaphones" in the wing tanks pointing back to the center tank) take the fuel from the wing tank and put it in the collector tanks, those two small blue rectangles in the center tank. They're about 11 gallons each. From there, fuel is drawn by the main ejectors (below the collector tanks pointing toward the engines), past the fuel SOVs (shut-off valves, #4), through the fuel filter to the engine. If ejector pressure is low for whatever reason, the boost pumps (the circles with P's in the middle right below the collector tanks) can kick in to provide the "oomph" for the fuel.

It's a slightly confusing synoptic, but the electrical ones are worse!

Hope this helps.

[Kyle Sanders]

It's a slightly confusing synoptic, but the electrical ones are worse!

Hope this helps.

Sir, I do not know your name (might want to make it a signature, they get kinda picky about that around here)

But i want to THANK YOU SO MUCH for that VERY informative response. This is going to help me out a GREAT deal.

I do have a couple more questions if you are available, it deals with performance and things of that sort that are a bit more advanced. If you are willing to help me out, can you please email me at ksanders7070@gmail.com and i will send you the information that i am inquiring about in the CRJ2.

Thanks again

[Cameron]

Sir, I do not know your name (might want to make it a signature, they get kinda picky about that around here)

I think you have us confused with someone else. PMDG maybe?

[Kyle Sanders]

I think you have us confused with someone else. PMDG maybe?

No, i may be mistaking but i thought when i first joined the forum that you kept reminding me to post my name at the end of my posts. I am sorry for this.

Edited March 30, 2012 by Kyle

[Cameron]

...i thought when i first joined the forum that you kept reminding me to post my name at the end of my posts.

Never once been a policy of ours.

[Kyle Sanders]

Ok, great. I will be more careful when advising others then

[Kyle Sanders]

I think you have us confused with someone else. PMDG maybe?

I have found out where i was mixing you up with... the NAVIGRAPH forum... they require a signature that states at least your first name lol

sorry for the false information posted here