CRJ-200 Fuel system

[atrdriver]

I’m good with most of this, but you shut off the boost pumps with “both” engines running? What do you look for?

Don't know that I have ever tried it, but I think all you would get is amber "l(r) fuel pump". You shouldn't get a lo press because the main ejectors would still be providing sufficient pressure.

 

[dbert]

Don't know that I have ever tried it, but I think all you would get is amber "l(r) fuel pump". You shouldn't get a lo press because the main ejectors would still be providing sufficient pressure.

Agreed.
So how do they know their onside motive flow is only feeding itself?

 

[Beanie]

Dbert, they wouldn't if they checked with both engines running.


You check the FUEL CHECK VALVE with one engine running, not both. That is the only way you will get the amber L and R BOOST PUMP INOP caution messages AND the (R or L, depending on which engine is shut down) FUEL LO PRESS caution message when you select the boost pumps off. If both engines are running you should only get the L and R BOOST PUMP INOP message because the Main Ejectors will provide the pressure needed......

The rest sounds pretty right on.

 

[Lear70]

Dbert, they wouldn't if they checked with both engines running.


You check the FUEL CHECK VALVE with one engine running, not both. That is the only way you will get the amber L and R BOOST PUMP INOP caution messages AND the (R or L, depending on which engine is shut down) FUEL LO PRESS caution message when you select the boost pumps off. If both engines are running you should only get the L and R BOOST PUMP INOP message because the Main Ejectors will provide the pressure needed......

All correct.

The operators who do First Flight of Day check valve tests see this pretty reguarly and, once they have it explained to them, have an excellent grasp of the system and what messages you will get when and why.