United Express Blows Tires Veers off Runway in Newark

[BobDDuck]

All the jets I've flown (Boeing's and Embraers) would transfer fluid via the shuttle valves. It's not a unique Embraer flaw.

There's no way to do it in the CRJs. Each of the three systems is entirely separate.

I see this as something kind of like pulling circuit breakers in flight.

Don't do it unless it's an emergency or the QRH tells you to.

 

[Nark]

The 170/190 doesn't transfer fluid, only power between system 1 and 2 through a Power Transfer Unit.

We can't "transfer" fuel either as pilots, but on the ground we can through a maint action.

 

[Polar742]

I didn't mean the fluid transfer as a means of procedure nor a means of a valve similar to a fuel crossfeed. I meant as a matter of the shuttle valves at the brakes.

The E145ish jets I remember you had to hold the toe brakes prior to setting or releasing the parking brake. If you didn't fluid would transfer as the shuttle valve moved.

The E170 I thought was the same, but Nark corrected that.

In the big Boeing, we have to pressurize hydraulics in a certain order to prevent fluid from passing around the shuttle valve.

 

[N519AT]

Certain Embraer products (-120 -135 -145) can get one hydraulic system low on fluid, and one hydraulic system with a lot of fluid, through improper application and release of the parking brakes (or if a seal has broken in the brakes—sometimes happens). Usually Green ("system one" on the -135 if memory serves) is low and Blue (system two) is pegged off-scale high (and occasionally puking fluid out through a nacelle drain mast). The fix for this is repeated setting and releasing of the parking brakes either with or without touching the toe brakes to transfer fluids between the systems.

(I believe this is best done on the ground, while chocked, personally, because landing with the brakes locked = blown tires and a carpet dance, and possibly worse.)

On the Dash, it's called hydraulic fluid migration and happens quite a bit. It happens when the CA applies the toe brakes, and while holding the toe brakes, applies the parking brake and releases the toe brakes. The fluid migrates from the #1 system to the #2 system. It's not a big deal to transfer it back, as it's just the same procedure as above but reversed. We can't do it in flight however because use of the main wheel brakes in flight is inhibited through the anti-skid system and WOW switches.

 

[Autothrust Blue]

On the Dash, it's called hydraulic fluid migration and happens quite a bit. It happens when the CA applies the toe brakes, and while holding the toe brakes, applies the parking brake and releases the toe brakes. The fluid migrates from the #1 system to the #2 system. It's not a big deal to transfer it back, as it's just the same procedure as above but reversed. We can't do it in flight however because use of the main wheel brakes in flight is inhibited through the anti-skid system and WOW switches.

On the Bro and BroJet, the parking brake is also the emergency brake, and the handle always works regardless of WOW.

Touchdown protection can get ridiculous sometimes, especially if the landing is a greaser. [EMB 120 crap follows...] The same circuits also unlock the flight idle solenoids that prevent PL movement below flight idle, so you can temporarily find yourself without stopping capability. Firm is preferable in, say, Carlsbad.

Use the emergency brake function...judiciously. (Read that as "never unless you have to.")

 

[Autothrust Blue]

yeah I only ever did that on the ground...

That handle (and a few other controls) have barbed wire around them in flight as far as I am concerned.

 

[N519AT]

On the Bro and BroJet, the parking brake is also the emergency brake, and the handle always works regardless of WOW.

Touchdown protection can get ridiculous sometimes, especially if the landing is a greaser. [EMB 120 crap follows...] The same circuits also unlock the flight idle solenoids that prevent PL movement below flight idle, so you can temporarily find yourself without stopping capability. Firm is preferable in, say, Carlsbad.

Use the emergency brake function...judiciously. (Read that as "never unless you have to.")

Yeah, it's the same as on the Dash. It functions as the e-brake and has it's own accumulator if all hydraulics are lost.

Our systems manual is kind of vague, but being that the emergency brake bypasses the anti-skid I would imagine that you could use it in flight...not sure why you would want to as you can't even transfer fluid because the main brakes (read: toe brakes) are inhibited with the anti-skid and WOW.

edit- also, because the e-brake function isn't protected by anti-skid you have to be VERY careful with using the e-brake as the handle (according to the systems manual) is VERY sensitive.

 

[Baronman]

Yeah, it's the same as on the Dash. It functions as the e-brake and has it's own accumulator if all hydraulics are lost.

Our systems manual is kind of vague, but being that the emergency brake bypasses the anti-skid I would imagine that you could use it in flight...not sure why you would want to as you can't even transfer fluid because the main brakes (read: toe brakes) are inhibited with the anti-skid and WOW.

edit- also, because the e-brake function isn't protected by anti-skid you have to be VERY careful with using the e-brake as the handle (according to the systems manual) is VERY sensitive.

Sounds like the same in the ERJ. Keep in mind even though we have the ability to transfer fluid using the E-Brake handle, I have NO idea why you would. There is no procedure requiring you to do so as a pilot. It's strictly a MX thing yet something we know about. Not even a low Hydraulic fluid warning requires you to do so.

As an e-Brake there is no anti-skid either. We usually practice one in the sim...it's wasn't so bad, just be very slow to add pressure.

 

[Bumblebee]

there is no feathering on the P-brake on the bro...it's on baby.