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User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Posted (13 years 8 months 3 days 2 hours ago) and read 1709 times:

Can someone explain to me what the purpose of each vent on the side of this DC10, under the "E" in Northwest, controls?


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I imagine the first vent is the outflow valve?

I imagine the secod valves function is live the manhole cover on the DC8 and prevents presurizing on the ground?

The third I imagine is the over pressure relief valve?

If theses vents are associated with the pressurization system then why are they located on the foward side of the aircraft and not on the rear bottom where they are usually found?

JET

14 replies: All unread, jump to last
 
User currently offlineFlyf15 From , joined Dec 1969, posts, RR:
Reply 1, posted (13 years 8 months 3 days 2 hours ago) and read 1614 times:

Although I don't know the answer to the questions, I once saw a a pic of a United DC-10 from the 1970s which had a brownish gold stain on the side comming from these vents...presumably from the cigarette smoke onboard.

User currently offlinePmk From United States of America, joined May 1999, 664 posts, RR: 2
Reply 2, posted (13 years 8 months 3 days ago) and read 1596 times:

JETPILOT:

As I have been told by an NWA ramp rat, that is one of the outlets for the A/C paks. It doesn't sound right to me but that's what I was told. But then again it was NWA, the pilots probably don't know!  Smokin cool

Peter


User currently offlineKonaB777 From , joined Dec 1969, posts, RR:
Reply 3, posted (13 years 8 months 3 days ago) and read 1586 times:

That vent is the cabin pressure outflow valve. The goldish brown stains are in fact from cigarette smoke back when airlines used to allow on-board smoking. Yuck!!! Thank god they outlawed it.

User currently offlineChdmcmanus From United States of America, joined Mar 2001, 374 posts, RR: 2
Reply 4, posted (13 years 8 months 3 days ago) and read 1580 times:

The actual nomenclature is the "Thrust Recovery Outflow Valve"; otherwise I believe your initial assumption is correct, although I'm not exactly sure what order they are in.


"Never trust a clean Crew Chief"
User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Reply 5, posted (13 years 8 months 3 days ago) and read 1583 times:

The 2 doors on the fusealge right above and in front of the nose gear are the pack cooling outflow doors.

Which is the "thrust recovery outflow valve" and why is it called that?

JET



User currently offlineChdmcmanus From United States of America, joined Mar 2001, 374 posts, RR: 2
Reply 6, posted (13 years 8 months 3 days ago) and read 1581 times:

The thrust recovery outflow valve is essentially the valve that controls cabin altitude throughout the isobaric selection range. It can be controlled electrically through 2 electric motors receiving input from the automatic and semi-automatic cabin pressure controller/computer. On the -10's with Flight Engineers, the clutches could be disengaged via a handle at the FE station, and the valve was then controlled through a manual wheel. I'm not sure about the later models. As far as the name is concerned, I guess it comes from the recovery of bleed air (thrust loss) to pressurization. It probably falls into the same category as why Lockheed re-named the short circuit as a "differential electrical fault"?? I'm not sure why they would put it there either. During Flight Engineer school, we covered some general DC-10 systems, and I work around them, but I have never flown one. Sorry I couldn't be more help on this one.

Regards
ChD



"Never trust a clean Crew Chief"
User currently offlineDc10hound From United States of America, joined Dec 2000, 463 posts, RR: 5
Reply 7, posted (13 years 8 months 2 days 23 hours ago) and read 1560 times:

JET,
The Cabin (Over) Pressure Relief Valves (Three each, why there are are three, I don't really know) are located on the opposite side of the fuselage, almost directly across from the cabin outflow and thrust recovery valves. They live just aft of the Forward Cargo Door. Sorry, I don't have a photo of these.
Check out a MD-11 sometime. You'll see only one cabin pressure valve in the same location as three on a 10.



"Eagles soar. But weasels never get sucked into jet intakes.."
User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4229 posts, RR: 37
Reply 8, posted (13 years 8 months 2 days 22 hours ago) and read 1548 times:

Thats the thrust recovery outflow valve, ram air vent, and butterfly valve for pressurization. The butterfly valve is closed when the plane gets airborone.


Chicks dig winglets.
User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Reply 9, posted (13 years 8 months 2 days 21 hours ago) and read 1549 times:

Going from foward to rear.....is the outflow valve, butterfly, and the ram air vent?

Whats the ram air vent used for?

Why is this on the side of the plane instead of the normal area back by the arse?

And I'm not getting the thrust recovery thing. What makes this outflow valve different from every other one on any other plane.

JET



User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3708 posts, RR: 34
Reply 10, posted (13 years 8 months 2 days 21 hours ago) and read 1544 times:
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Going from front to rear:-

1) The Outflow Valve Ram Air Shield.
Normally this is closed but is driven open during TO roll, rotation & ldg to deflect the airstream & create a low pressure area over the outflow butterfly valve.

2) The Outflow Butterfly valve.
Controls the outflow of cabin exhaust air to maintain cabin pressure during low flight altitudes & low diff pressures.

3) Thrust Recovery Valve.
This valve controls pressurisation during moderate to hight flight Alts. It is so called due to the fact they can recover some thrust as the air spills out.

As the throttles are opened for TO the butterfly valve will modulate towards closed.

I know of one incident when someone, who should have known better, was watching from his office a '10 line up at LGW, saw a hole in the side of the a/c and got it to return to the gate. Only to find out that what he had been looking at was the open butterfly valve.

Finally, you can declutch the outflow valve sys on all '10's


User currently offlineJETPILOT From United States of America, joined May 1999, 3130 posts, RR: 29
Reply 11, posted (13 years 8 months 2 days 20 hours ago) and read 1540 times:

Thanks guys just what I was looking for.

Strange place to put that stuff.

JET


User currently offlineDC-9CAPT From , joined Dec 1969, posts, RR:
Reply 12, posted (13 years 8 months 2 days 17 hours ago) and read 1537 times:

Since this is such a good digital photo and I know nothing about the DC-10,
could someone explain what those two, equally sized access panel doors are? These doors are right below the forward entrance and left and below the flag.
I assume they are for servicing the nose gear or avionics.


User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4229 posts, RR: 37
Reply 13, posted (13 years 8 months 2 days 16 hours ago) and read 1529 times:

Just for your enjoyment, this is my last day of school, ill be heading home tommorrow, so i will type up a detailed description of the NW DC-10 pressurization system from my dad's AOM.


Chicks dig winglets.
User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3708 posts, RR: 34
Reply 14, posted (13 years 8 months 2 days 15 hours ago) and read 1517 times:
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They are access doors to the a.c packs. #2 Pack fwd #1 pack aft.

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