Emb145 hyd sys 1 & 2 fail

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12-08-2011, 03:59 AM

Oscar13601

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Emb145 hyd sys 1 & 2 fail

What is the cause if anybody knows about when you release the Parking/Emergency Brake with Hyd Elect Pumps off at the gate and you get a HYD SYS 1 & 2 FAIL eicas msg.?????

12-08-2011, 08:27 AM

ERJF15

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Quote:

Originally Posted by Oscar13601

What is the cause if anybody knows about when you release the Parking/Emergency Brake with Hyd Elect Pumps off at the gate and you get a HYD SYS 1 & 2 FAIL eicas msg.?????

Does the CA turn the pumps on before releasing the brake and then turn them off after the brake is set again w/electrical power applied?

12-08-2011, 08:52 AM

meeko031

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from my understanding of the system, if the elec hyd pumps are off(#2 for emer brake)you will get a hyd fail because the pressure is less than 1300psi!

does that sound about right????

12-08-2011, 10:58 AM

Oscar13601

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I think you are right Meeko031....

12-14-2011, 04:30 PM

nocnik

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By actuating the parking brake you are taking hyd pressure from the system for the brakes. If the accumulator has bled down to far and system pressure drops below 1300 psi i you will get hyd1&2 fail msg. on the EICAS. All this is of course without any hyd pumps in operation.

01-01-2012, 10:34 PM

Great Cornholio

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Quote:

Originally Posted by Oscar13601

What is the cause if anybody knows about when you release the Parking/Emergency Brake with Hyd Elect Pumps off at the gate and you get a HYD SYS 1 & 2 FAIL eicas msg.?????

My guess is that it has something to do with the EICAS logic. It doesn't matter if the accumulator is bled down or not. You will always get that message as soon as you drop the brake. For what ever reason EMB is really big about keeping the EICAS clean. Just think about how the low oil pressure, eng out, etc messages never show up on the ground. I think the guys at EMB decided that if you have the brake set you don't care that the hyd sys is failed so the message is inhibited. If you don't have the brake set then they figure you are about to move the plane and therefore now care that the hyd sys is failed so the EICAS message is presented. Thats just my guess I have no reference to support my theory aside from 8 years on the 145.

01-02-2012, 05:19 AM

Jones14

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It means your mechanics aree not servicing the emergency brake accumulator on their line checks. Should be around 2000 psi when fully released. There's also a pressure switch that can go bad, which is deferrable. If deferred there will be an associated MEL-02 for a daily check of the accumulator pressure, and line mechanics hate it.

I never told you any of this