CTR
Topic Author
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Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 2:26 am

On pressurized cabin civil aircraft carrying approx 100 to 120 passengers, are hydraulic lines for controls and landing gear run through the cabin? Or are they some way isolated from the cabin in the event of a leak.

My background is as an engineer on military aircraft (F/A-18, AV-8B, F-15) where all flammable fluids running in the cockpit are prohibited by MIL Spec. Recently however I started working on a new passenger aircraft with an ex Boeing engineer, and he claims that Boeing runs hydraulics through the pressurized passenger and pressurized cargo cabin sections all the time.

Is this true?

Take care,

CTR
Aircraft design is just one big compromise,,,
 
Boston92
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 3:14 am

I really don't know, but on one Sun Country Flight I was on, one of the overhead bins, had no backing on it, and there was stuff that sure looked like hydrolics.
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Tristarsteve
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 3:17 am

Yes hydraulic and fuel lines run through the pressure cabin.
The fuel lines are shrouded and any leaks go overboard via a tell tale, but the hyd lines run through the freight holds.
 
OldAeroGuy
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 3:28 am

Quoting CTR (Thread starter):
Boeing runs hydraulics through the pressurized passenger and pressurized cargo cabin sections all the time.

It's hard to keep hydraulic lines running to the nose gear actuator/steering or the elevators/stab trim/rudder out of the pressure vessel without external fairings. However, they are seldom in the passenger area per se. The cargo hold is a more common location.

Airbus and Boeing have addressed this design issue in similar manners.

[Edited 2006-08-27 20:37:48]
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MCIGuy
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 3:35 am

I don't know about civvie's, but it's done in military transports all the time. If you've ever been up in a C-5 there are lines running everywhere.  Smile
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troubleshooter
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 3:53 pm

I remember one accident with a BAe146 where a hydraulic line wich was routed through the passenger cabin failed and several passengers were injured by the skydrol and its fumes. Unfortunately, I can´t find any details...
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777wt
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 4:30 pm

Yes the same holds true for the ERJ-145.
 
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HAWK21M
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 5:09 pm

I may not win often, but I damn well never lose!!! ;)
 
Lucky42
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RE: Hydraulic Lines Run Through Passenger Section?

Mon Aug 28, 2006 5:37 pm

Really the only time you really need to be worried about skydrol in the cabin is on the high wing aircraft like the bae146/RJ-85 Mesaba had it happen not all that long ago on an RJ-85.
 
avt007
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RE: Hydraulic Lines Run Through Passenger Section?

Tue Aug 29, 2006 9:44 pm

"Really the only time you really need to be worried about skydrol in the cabin is on the high wing aircraft like the bae146/RJ-85 Mesaba had it happen not all that long ago on an RJ-85."
I have seen leaks like that on a Dash8, but a worse scenario happened on an F28 where a susbstantial leak caused a skydrol mist to spread through the cabin. Of course the F28 is unusual in having the hydraulic manifolds inside the fuselage.
 
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HAWK21M
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RE: Hydraulic Lines Run Through Passenger Section?

Wed Aug 30, 2006 1:07 am

Quoting Avt007 (Reply 9):
Of course the F28 is unusual in having the hydraulic manifolds inside the fuselage.

What systems were these routed to.
regds
MEL
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silentbob
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RE: Hydraulic Lines Run Through Passenger Section?

Wed Aug 30, 2006 3:07 am

You see leaks in the Dash cabins all the time.
 
SFOMB67
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RE: Hydraulic Lines Run Through Passenger Section?

Wed Aug 30, 2006 9:41 am

I haven't been around military aircraft for a good many years, but they used 5606 then, compared to commercial aircraft using skydrol.
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troubleshooter
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RE: Hydraulic Lines Run Through Passenger Section?

Wed Aug 30, 2006 11:51 am

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SFOMB67
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RE: Hydraulic Lines Run Through Passenger Section?

Thu Aug 31, 2006 7:10 am

I am surprised that they would route the hyd lines in the ceiling. I think it's pretty common to have them under the cabin floorboards, though. Yes, the passengers would have a hard time breathing with a cracked hyd line atomising skydrol in the cabin. I'm sure they won't forget that experience for awhile.
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EMBQA
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RE: Hydraulic Lines Run Through Passenger Section?

Thu Aug 31, 2006 7:28 am

As of the Saab 340.. the answer is No. There are no hydraulic lines in the passenger cabin. I can only guess that the Saab 200 is the same, but I don't know for sure.
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Starlionblue
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RE: Hydraulic Lines Run Through Passenger Section?

Thu Aug 31, 2006 8:06 am

Quoting Sfomb67 (Reply 14):
am surprised that they would route the hyd lines in the ceiling. I think it's pretty common to have them under the cabin floorboards, though. Yes, the passengers would have a hard time breathing with a cracked hyd line atomising skydrol in the cabin. I'm sure they won't forget that experience for awhile.

With a high winged aircraft, you pretty much have to run lines in the ceiling.
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