High altitude takeoff / landing

[earthdog 605]

Hi All! I have been trying the SLLP-SPZO route yesterday, and i would like to get some insight on where i can find in the manuals the relative actions regarding high altitude takeoffs and landings... In FCTM i cant seem to find something relevant except "reduced thrust takeoff" part... Can someone specifically for this bird explain some bits regarding the procedures followed in such a takeoff / landing?

[Guest tonyf38]

Hey there Earthdog, Just like any aircraft, the higher the airport elevation, the engines won't perform like they would at sea level.. Pilots have to be specially trained and certified to depart and approach high altitude airports.. That's why an airport here in the US like KDEN has a minimum length runway of 12,000 ft because you'll eat up a lot more runway on takeoff and landing.. Basically, it will take longer to reach Vr and you have to be aware that late in the takeoff run, the aircraft's groundspeed will be a lot higher than the indicated airspeed, so you have to trust v1 vr v2 instead of what your eyes are telling you when looking outside.. On landing, your groundspeed will be so fast it will give you the illusion that you're approaching at too high a speed.. In the 737 let's say departing SPZO, flap 5, but step on the toe brakes until about 80 percent N1, then let er rip.. You'll notice that you'll have to keep the nose at 10 degrees early in the climb and get it cleaned up quickly to give you better climb performance.. For approach and landing, your groundspeed will be much higher than indicated, so the descent will be shallower on final, flaps 40, and autobrake 3 , and with a higher throttle setting than landing at a lower airport.. That's what high altitude airport training is all about, trusting what the instruments tell you rather than the sensations you'll be experiencing just like in IMC weather..

[henri5 16]

And don't forget that for the reasons mentioned, your maximum takeoff weight is less than at normal altitude, so if yhou are having trouble taking off, throw some passengers or cargo overboard.

[Ralgh 43]

The max altitude for takeoff and landing for the 737 is 8,400 feet according to the limitations in our manuals at American. I don't know if there are any differences for other 737s to do high altitude operations.

[Guest tonyf38]

The max altitude for takeoff and landing for the 737 is 8,400 feet according to the limitations in our manuals at American. I don't know if there are any differences for other 737s to do high altitude operations.

There's a 12,000 ft option for airlines that operate at High Altitudes..

[Ralgh 43]

I did not know that. After ten years I'm still learning things about the 737. Of course SLLP is over 13,000 feet so that could still cause a problem.

[M_Sauce 6]

I would venture most of the mods deal with passenger O2 systems and some of the automated warnings. Besides that, if the performance is calculated, then you are off. As far as procedures, you could probably expect to have to manually configure the pressurization during landing and takeoff. Probably one of the few times where the cabin would actually climb during landing and descend during takeoff. Make sure you disable any automatic mask deployment as well. Don't want to drop the rubber jungle just before landing if you don't really need to. Having said that, I'm sure a somewhat underpowered light-twin like the 737-800/900 struggles quite a bit to make it off the ground at high elevation airports with any significant load (The 700 and 600 might be a different story though). That is probably why you don't see many of them operating at the high elevation airports. These days it is mostly A320/319s, B757s, and A330s in modern airports, and you still see a lot of low-bypass jurasic-jets at the older spots.

[Paul Deemer 13]

You won't see any 737-800s taking off in the real world from SLLP. Even with the 12,000 foot High Altitude Option which is not modeled in the NGX yet, SLLP would still be too high. American Airlines does service SLLP with a 757 which can take off at altitudes up to 14,000 feet. The 787 also did trial runs at El Alto (SLLP) so it is rated for that altitude as well. Because of the extreme height and thin air at that altitude that is why the runway is 13,600 feet long and why you don't see any heavies taking off from there. With a 13,600 foot runway at normal altitude a fully loaded Concorde or Airbus 380 could take off easily. At a takeoff altitude of 13,325 feet they would never make it off the runway. The 757 is not classified as a Heavy, and is way overpowered which makes it ideal for SLLP. The 787-800 would be considered a Heavy but its got Next Gen Engine Technology on it. I found this out doing some research cause I tried to take off from SLLP in the MD-11 and even with a light load I couldn't get off the ground and I had numerous warnings in the cockpit about the altitude, so I guess it is modeled in the MD-11. The 747-400 I was able to get off the ground but it took the whole runway and I did not get any warnings probably because it is not modeled. Without the 12,000 foot High Altitude Option the Aircraft are rated as follows.MD11 - 10,000 ft747-400 - 8400 ft737-800 - 8400 ft

[Sorelimbs 0]

And don't forget that for the reasons mentioned, your maximum takeoff weight is less than at normal altitude, so if yhou are having trouble taking off, throw some passengers or cargo overboard.

Hehehe

[earthdog 605]

thanks guys! Take alook at this: http://www.captainpilot.com/files/BOEING%20PERFORMANCE/High%20Altitude%20Operation.pdf Indeed a 757 is more suitable..

[M_Sauce 6]

You won't see any 737-800s taking off in the real world from SLLP. Even with the 12,000 foot High Altitude Option which is not modeled in the NGX yet, SLLP would still be too high. American Airlines does service SLLP with a 757 which can take off at altitudes up to 14,000 feet. The 787 also did trial runs at El Alto (SLLP) so it is rated for that altitude as well. Because of the extreme height and thin air at that altitude that is why the runway is 13,600 feet long and why you don't see any heavies taking off from there. With a 13,600 foot runway at normal altitude a fully loaded Concorde or Airbus 380 could take off easily. At a takeoff altitude of 13,325 feet they would never make it off the runway. The 757 is not classified as a Heavy, and is way overpowered which makes it ideal for SLLP. The 787-800 would be considered a Heavy but its got Next Gen Engine Technology on it. I found this out doing some research cause I tried to take off from SLLP in the MD-11 and even with a light load I couldn't get off the ground and I had numerous warnings in the cockpit about the altitude, so I guess it is modeled in the MD-11. The 747-400 I was able to get off the ground but it took the whole runway and I did not get any warnings probably because it is not modeled. Without the 12,000 foot High Altitude Option the Aircraft are rated as follows.MD11 - 10,000 ft747-400 - 8400 ft737-800 - 8400 ft

Well, technically the 757 is indeed considered a heavy. It is all about thrust to weight ratios, any airplane that lacks excess thrust is gonna struggle in a hot and high environment. Actually, the MD-11 is a very good hot and high airplane. I think it did certification in Tibet if I am not mistaken. But I am sure it can't take off at max weight when that high. And an A380 could probably take off from a high elevation airport quite fine. It is just that your load and/or range would suffer, making it uneconomical in most circumstances. Keep in mind that more engines will give you better high altitude performance in most cases. All takeoff performance calculations are based on loosing one power-plant, so a four or 3 engine airplane is only loosing 1/4 or 1/3 of its thrust while a twin is loosing 1/2. That is why twin engine airplanes have higher thrust to weight ratios. A 747-400 is not certified to be able to continue the TO after 50% of its thrust (ie, 2 engines) at max TOW - but a 777 or 767 certainly can continue the TO after loosing 50% of its thrust at max TOW. So it is a little more complicated than just the size of the airplane.

[henri5 16]

FWIW, I started at Denver with the NGX 800WL, loaded full fuel and cargo, programmed a flight from KDEN to KLAX with an OAT of +20C and took off manually. The vref was 152, and I got up just before the end of the runway. So this plane CAN take off from KDEN (although in real life your AH might be yelling bravo as you approach the end of the runway...). Henri

[michal 44]

Well, technically the 757 is indeed considered a heavy. I

It is not. It simply is grouped together with "heavy" for the purpose of distances on final and wake turbulence. You can even read in FAA docs "...heavy and 757..".

[DVA4890 0]

Delta does ATL-DEN and back but it most have the high atl ops in them and same with Air Tran i think

[M_Sauce 6]

It is not. It simply is grouped together with "heavy" for the purpose of distances on final and wake turbulence. You can even read in FAA docs "...heavy and 757..".

What other purpose is there?