Trufactor,

It's been 7+ years but I'll try and answer this for you. The CRJ like most modern cockpits works off the dark cockpit principle. That means when all systems are powered and you are at the end of the runway ready for takeoff, the cockpits dark. Any light on would signify there is a non-normal condition. Not necessarily abnormal, just non-normal.

In the case of the boost pumps, when selected prior to engine start the pumps come on when pressed in and the lights are on to signify they are working. In this case, it is a status message which means that the system is letting you know its not normal for the boost pumps only to be on but they are working. The reason they are status lights is because the boost pumps are only used until there is sufficient fuel pressure from the engine driven pumps and primary ejectors to take over the load. The engine driven pumps boost the fuel pressure to around 800 psi whereas the electric pumps are around 50 psi I think. That's why if you lose an engine driven pump the engine fails no matter how many electric pumps are available.

The electric pumps only exist to provide positive pressure to the engine driven pumps and augment the primary ejector. The primary ejector has no moving parts and is simply a siphon. Once you get suction from it, it stays on until you stop the flow. At some point during engine start, the primary ejector gets enough suction pressure to take over the load from the electric pump. The system senses this and the electric pump which was selected on, goes into a standby mode. If for any reason, the electric pump senses low pressure to the engine driven pump, it turns on to ensure positive pressure to the engine driven pump.

Since the electric pump is in standby, you don't have any lights on. The only reason you would get an electric pump light following engine start is if there is a primary ejector failure, or an engine is shut down.

Its been awhile but hope that helps. I spent a lot of time on the RJ years ago. IMO, it was the most challenging plane from a systems standpoint to learn. Once learned however, its hard to forget and is a very straight forward airplane. Good luck. You will enjoy it.

Let me know if you need any help with AUTOXFER FAIL.

 

The engine should still run because of the suction from the EDP. However, the only reason the other boost pump wouldn't come on if I remember is if you manually select the L Boost Pump Off in this case. However, since you didn't do that I have no idea why that would happen.

 

Motive flow! Baby; Motive flow!

 

That's one of the better avatars that I've seen in a while.

 

Now let’s not confuse the issue.

Let’s see, L(R) FUEL LO PRESS master caution illuminates at 5 psig to indicate that a low fuel pressure condition (at the engine inlet) has been detected. During which phase of flight and under what conditions did you experience this?

And… to reply to other posts…

Just to be clear, there is no AUTOXFER FAIL caution, advisory, status, or other message if that is what you were getting at. L(R) XFLOW SOV FAIL or XFLOW/APU PUMP master cautions are related to “failures” of the automatic crossflow operation.

BOOST PUMPS. Breakdown L(R) Fuel Boost Pump Switchlights:

Pressed In – For engine starts, both boost pumps are activated (“ON” light illuminates). With engines running, (“ON” light extinguishes with sufficient fuel pressure), boost pumps remain armed and automatically come on when low fuel pressure is detected in any engine feed line. Switchlights show ‘ON’ when pumps are operating.

Pressed out – The boost pumps are disarmed.

INOP light illuminates when:

1. Low boost pump pressure (engines off),
2. Boost pump not armed (engines running), or
3. Has failed.

 

WOW... simple question has turned out dozens of VERY detailed and correct answers. Gotta luv systems... But yeah Motive flow! Better start hitting the books myselfs again incase my Loft turns to a PC.

 

My comment about AUTOXFER FAIL was kind of a joke not related to anything fuel but electrical. I remember a lot of guys were confused by AUTOXFER FAIL and AUTOXFER OFF back in the day. Again though, this is all from memory from a long time ago. However, it shows you how much they made you know back in the day to think it's still with me. There is very little I remember about the 737-200 but a CRJ I can talk all day long. Many a late night candle was burned for the airplane when in initial and upgrade.

 

I can never be the first on to answer these questions

 

Another question for you CRJ guys...ive looked through my study guide and could not find the answer to this and you guys were a lot of help on my first question...when taking off it says to select TOGA and set N1 70% power for takeoff..does selecting TOGA mean flipping a switch or what exactly does it mean??? thanks in advance

 

2F5, 4A1- k i'm good for the checkride.