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guy

777 Pressurization and high altitude airports

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I am on a tour through South America with the 777.Flying from Santiago(Scel) to La Paz(Sllp) situated at the altitude of 13300 ft, the red cabin altitude text went on during cruise at 39000ftThere was more then an hour to go and the cabin altitude was already at 13300ft,which is the destination altitude. I looked up in the manual and found nothing concerning the pressurization.So I had to try by setting the two outflow valves to manual and playing with the open/close buttons I managed to get the cabin altitude back to 8000 ft.I pulled and turned also the right button , takeoff and landing altitude, but it seems to do nothing.On the short hop from LaPaz to Cuszo (Spzo), situated at 10800 feet I had an eye on this.After takeoff during climb the Cabin altitude goes slowly down from 13300 to about 8000 feet,but then ,at cruise altitude, it immediatly goes up again (with a rate of 250) to the destination altitude which in this case was 10800 feet and the red warning goes on. Same thing happened on the way from Cuszo to Quito (Sequ) at 9300 feet.I think the fact that the cabin altitude goes immediatly up to the destination altitude at cruise is not normal, or is it?. Took the A330/A340 several times to those airports and never have seen this.Great plane , the 777!Guy

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I had the same problem the other day at SLLP. The takeoff and landing altitude switch did nothing and the cabin altitude remained in the red. Not sure if this is an error or if there is a procedure to correctly set the cabin altitude at these heights.Appart from this and the stuttering FPS/gauge issue, its a great aircraft to fly.

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As I said in my message, you can change the cabin altitude by setting to manual the the two outflow valves, for and aft, on the left of the landing altitude button (which effectively seems to do nothing), and then use the open/close buttons below. When you open the pressure goes down, When closing it goes up.You can follow what happens on the MFD (air page).Guy

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777 Operating Limits:Maximum Takeoff and Landing Altitude: 8,400ft Pressure AltitudeThats probably why you have a problem, you are breaching the laid down limitations that Boeing have set.Cheers

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Thanks for the information.Seems nevertheless astonishing.The take-off runway-length tables of Pss go up to 13-14000 feet!There are regular A320, 737 and old 727 going into La Paz (13300 feet, SLLP) and I also know that they did high-altitude tests with the A340 at SLLP with even V1-cuts.And the powerful 777 cannot?Guy

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For the 767 the limit take-off altitude is also given as 8400 feet pressure altitude in the doc I have , but there are 767 (and also other heavies like MD11, A340) going out of Quito(Sequ) which is situated at 9300 feet.Guy

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Have looked up things: For the 757 the same limit of 8400 feet maximum pressure altitude for take-off and landing is given in the book.But: American Airlines goes to SLLP(13300ft) with the 757!(and UPS seems also)So this seems to be more a theoretical limitation.Guy

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