Cabin press. question landing at 13,000 ft

hotwings402

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How do you set the cabin press. if your landing in La Paz Bolivia where the airport is 13,000 feet? If the cabin altitude is 8000 feet won't there be a negative pressure?
 

njcapt

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If you failed to set the pressure controler for landing field elevation the negative pressure relief valve would prevent the cabin from being higher than ambient.

To be any more specific, I'd have to know how the system on you aircraft worked.
 

hotwings402

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Well heres the deal your at 350 at a cabin pressure of 8000 feet. At what point does the cabin pressure start rising to 13000? Or does it equalize on touchdown?
 

hotwings402

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Also......LOL Does the crew have to be on 02 when they report for duty....12,500 and above. he he
 

CSY Mon

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Yeah, ya start raising the cabin about 30 minuttes before landing..If memory serves right.

Also push the button on the modifed aiplanes to prevent the rubber jungle from dropping.

As the cabin comes up through 10,000' the cockpit crew goes on oxygen and we stay on the masks for approach and landing.

Also using the masks when we program the FMCs and read the before start checklist as well as for T/O and climb.

After T/O the cabin slowly comes down and at 10,000' or below cabin altitude we ditch the masks..

The terminal in La Paz have emergency rooms with oxygen bottles for the folks who faint.

Try smoking a cigarette in La Paz for a good buzz.....:cool:
 

Benhuntn

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I have landed at La Paz twice. What we did in the 757. We hit an override switch that prevented the masks from dropping. We then went on O2 prior to our descent. The pressure controller brought the cabin alt. up to the field elevation on our enroute descent. Just as a side note we ate at the Burger King in the terminal. The highest one in the world....
 

C-150ETOPS

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Only airport in the world that turns a 757 into underpowered, runway hogging sled :D

If I remember right, groundspeed at touchdown was around 175 knots. On takeoff, the mains broke ground around 195 knots.

The pressure info from the other guys is spot on. The O2 masks make it fun after you've developed a snotty cold on your way down. After departure we start running the cabin down. At around 8000' cabin alt, It feels like you can actually think and reason again.

Another highlight is all the little kids puking in the aisle after arrival.
 

Snakum

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If I remember right, groundspeed at touchdown was around 175 knots. On takeoff, the mains broke ground around 195 knots.
Wow! :eek: :eek: :eek:
 

jknight8907

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A guy at FlightSafety in Lakeland told me about when he used to be a C-141 pilot, and flew into La Paz. He said they had to raise the cabin altitude, then land at some ungodly speed, then walk around with an O2 bottle taking a hit off it every few minutes....
 

Panel Monkey

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jknight8907 said:
A guy at FlightSafety in Lakeland told me about when he used to be a C-141 pilot, and flew into La Paz. He said they had to raise the cabin altitude, then land at some ungodly speed, then walk around with an O2 bottle taking a hit off it every few minutes....

Ha...did that. Smoked a ciagarette then sucked some O2. La Paz is a bit rough for us flatlanders.

The engineer would set the pressurization (desired cabin altitude) to the forecast field pressure altitude so that the aircraft would become completely depressurized just prior to landing. I was always supremely happy when the gear was up leaving that place.
 

seethru

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So I take it there is not too many single engine props (C172s) operating out of La Paz.

The place sounds interesting to visit. What's the city/town like?
 

wrxpilot

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C-150ETOPS said:
Only airport in the world that turns a 757 into underpowered, runway hogging sled :D

If I remember right, groundspeed at touchdown was around 175 knots. On takeoff, the mains broke ground around 195 knots.

Wow! What is the speed limit on the tires??
 

KigAir

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After T/O the cabin slowly comes down and at 10,000' or below cabin altitude we ditch the masks..

How slowly? Is there a standard rate at which cabin pressure is changed?
 

enigma

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C-150ETOPS said:
Only airport in the world that turns a 757 into underpowered, runway hogging sled :D

If I remember right, groundspeed at touchdown was around 175 knots. On takeoff, the mains broke ground around 195 knots.

l.

Sounds like a MD80 at Vegas in the summertime. :eek:

enigma
 

Crzipilot

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Certain bolivian carriers operating 727's out of there w/o the modified pressure controller (switch to keep the jungle from coming down) Well you'd wind the Pressure controller all the way past 8.7k....raise the QnH dial all the way up..... Once the cabin stopped coming up, you'd turn one pack off then the other. Trick was on the 727 back in the cabin in a access panel in the floor was the reset T handle for the masks.. With it in the pulled out position the masks wouldn't drop for anything. Company would switch back and forth on that procedure, a good f/e could raise the cabin and the masks still wouldn't drop. Anyways flew out of there for a year or so, 80kts by the intersection or reject.
Also after doing a few overnights there, you get used to it, even able to go out drinking and dancing.....1 or 2 beers and your toasted, great cheap dates..LOL
 
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