CRJ 14th DUCT Msg...

[chperplt]

The QRH procedure for this message is to retard the affected thrust lever to idle and leave at idle. If the warning message goes out, you still leave the lever at idle and land at the nearest suitable airport.

What is the logic behind leaving the thrust lever at idle and landing single engine if the message goes away? You can verify the problem is gone on the synoptic page. I don't disagree with landing as soon as possible, but I'm not getting the single engine part with the message resolved.

Thanks

 

[rbowen]

need to know if it is a wing duct you are talking about, or a 10th or 6th stage bleed duct.... if a 6th or 10th stage bleed air duct, you would not want to use that engine for obivious reasons, leaking duct with extremely hot air going through it going into places that it is not suppose to be. the end result could be very bad...

 

[Mayday911]

My guess is to keep the output air temp. from the 14th stage as low as possible. The theory being that hot air being where it is not supposed to be is a bad thing. Fuel and Hydraulic lines and things like that.

 

[F70pilot]

"What is the logic behind leaving the thrust lever at idle and landing single engine if the message goes away?"

14th stage is high pressure. Even if you can get the message to go away by reducing thrust the leak remains. If you advance the thrust lever the leak will once again trip the bells & message. By leaving the lever at idle the leak won't cause any thermal damage, the engine will still provide: idle thrust, electrical power and low pressure bleed to the packs.

 

[chperplt]

Makes sense

thanks

 

[sabreliner]

need to know if it is a wing duct you are talking about, or a 10th or 6th stage bleed duct.... if a 6th or 10th stage bleed air duct, you would not want to use that engine for obivious reasons, leaking duct with extremely hot air going through it going into places that it is not suppose to be. the end result could be very bad...

Where do you fly that you never flew the 200? At ASA and I think CMR, we all train on the 200 and then the 700 guys go to differences. Just curious who has a 700 only program.

On the 200 you have 10th and 14th stage bleed systems and they are not interconnected. Very different from the 6th/10th system on the 700. Don't go getting other people confused...

 

[CF34-3B1]

Where do you fly that you never flew the 200? At ASA and I think CMR, we all train on the 200 and then the 700 guys go to differences. Just curious who has a 700 only program.

Eagle doesnt have any 200s. Maybe Horizon? Not sure who else.

 

[DoinTime]

On the 200 you have 10th and 14th stage bleed systems and they are not interconnected. Very different from the 6th/10th system on the 700. Don't go getting other people confused...

I believe the -200 uses 6th-stage bleed air as well to pressurize oil seals. Not commonly taught material though.

 

[CesnaCaptn]

One more thing that I didn't see mentioned. If the message goes away, it doesn't mean the leak went away. It just means you lost your ability to detect a leak. That is why you leave the thrust at idle.

 

[Sioux115]

I thought it was the 7th stage for oil seal pressurization?

 

[sleeve]

ha, i know this..it is the 7th for pressurization of the seals.....recurrent here I come

 

[DHPFLYN]

Horizon only has 700's

 

[chperplt]

BUT

You get the warning message and close the L or R 14th stage SOV. IF the valve is closed, how could the leak continue to damage inside of that SOV if you continued to use the engine?

Does the SOV not stop the air completely?

 

[cl-65link]

Stop thief! Somebody stole my avatar.

 

[DirkkDiggler]

When you close the 14th sov, you are only commanding the valve to shut. If you look on the synoptic page, you will see a CMD above each of the valves. Just because you closed it and the valve on the synoptic page shows it to be closed does not mean that the valve is really closed. It only shows the commanded position. Don't know if this is the answer but at least it's a guess.

 

[J41CA]

As mentioned the reason for the QRH procedure is to reduce the hot bleed air from thermal damage. 14th stage bleed air lines run through the pylons to the PRSOVs to the CMD valves out to the cowls and up the fuselage to the wing piccolo tubes. The bleed air leak can be anywhere and can cause significant damage. There is no guarantee that PRSOVs will close or leak. Therefore, the QRH procedure is to protect against that any significant amount of bleed air will get downstream to the duct failure point.

Depending on the EICAS message and aural you can pinpoint the area of the duct failure. If you recieve a L or R 14th Duct Fail EICAS message and a "Bleed Air Duct" aural, then the leak is between the PRSOV and either the wing or cowl CMD valve, which will be depicited red on the anti-ice synopic page. Plus, the associated L or R 14th SOV PBA on the Bleed Air Panel will have a red Duct Fail light.

If the aural is "Anti-Ice Duct", then the leak can be isolated from any point inside the wing CMD valve up to the wing. The section of the Anti-Ice synoptic that is red will either be the pipe along the fuselage or the wing is the area that has the leak. the duct along the fuselage has a single loop fire wire and the wing has thermal sensors behind the piccolo tube. This situation would present a red duct fail light on the Anti-Ice panel.

Another possible condition is a wing overheat, which basically is determined by thermal sensors in front of the piccolo tube attached to the wing looking for high temp. conditions. Wing overheat conditions may or may not be caused by a bleed air leak.

I hope the helps.

 

[DoinTime]

I thought it was the 7th stage for oil seal pressurization?

I'll buy that.