Maximum pressure altitude for takeoff in the MD-11 is 10000 feet, so that may answer some questions as far as performance from airports higher than that. This is from an actual FCOM.

Well, At first thanks for your reply. I took a look at the Environmental Envelope diagram and its not so clear, but i think you are right. But that got me to think, what aircraft can operate in such altitude?

The VC10!!!!!!!!!!!!!!!!!!!!Vololiberista

Martinair is operating many SEQU flights aswell for SKBO with the MD-11. They have most of the times max 2/3 payload (not maximum payload per pallet) and minimum fuel for a short trip (which is min fuel + altern and if needed some extra). Flap 25 and flex 53 (PW) 50 (GE) should do the trick with a brake on TO to spool up the engines. Trip flight from SEQU is to SEGU.SKBO to SEQU or TJSJ.John

Absolutely correct. Paul Smith is wrong 100%. There were quite a few deadly accidents when people attempted to takeoff from short grassy fields and they tried to shorten their takeoff by deploying more flaps - they often succeeded but then they could not clear trees at the end of the runway because their climb angle was too small. In one such accident a whole family perished a few years ago in British Columbia.It is enough to look up procedures for best climb angle in many smaller aircraft POH's - Vx - they all call for no flaps. The relation between more flaps and worse climb angle is pretty much universal, I personally would like to know if there is any exception to this rule.

100% wrong? Accidents when using too much flap on a short field leading to obstacle clearance issues, and I am suggesting the use of less flap? I would say I was 30% wrong at most, and that mainly in my description. It remains the correct advice in this context. If you doubt me, then try the same maneuver at Flaps 50. My reasoning was that given that engine thrust, take off weight and runway length are constant* then less flap = higher Vr, but less flap also = lower drag. Lower drag means less distance to reach the same speed (from F=ma where a = (thrust minus drag)) so the equation becomes a balance between the available runway length, the distance required to reach Vr25 and the distance required to reach Vr15. In this case, the runway was not long enough to reach Vr25, so the answer was to use Vr15. *[ We ignore failures because a higher Vr speed requires a longer braking distance which must be factored in to normal operations, but normal operations do not include high weight take-offs from SLLP :) ]

Yes Paul, your statement that flaps increase climb angle was dead wrong. No amount of spinning Newtonian physics will erase it. That would have been a wrong answer on your written PPL test. Rob also noticed your error.

Try the "Standard VC10" at full AUW. Because of it's hot and high performance all the pilots practiced/and still do (as it still flies) a short field take-off even at Heathrow!! Stand on the brakes, firewall the throttle, when the engines have spooled up let go. At V1 ease back on the control column taking the weight of the nose wheel. But don't unstick until Vr.Then climb out at 1,900 fpm !!!I don't think any existing jet transport compares.Vololiberista

Martinair is operating many SEQU flights aswell for SKBO with the MD-11. They have most of the times max 2/3 payload (not maximum payload per pallet) and minimum fuel for a short trip (which is min fuel + altern and if needed some extra). Flap 25 and flex 53 (PW) 50 (GE) should do the trick with a brake on TO to spool up the engines. Trip flight from SEQU is to SEGU.SKBO to SEQU or TJSJ.John

I don't think using flex on such high altitude will be useful, as you need so much thrust so you don't need to reduce it.

This is not SOP, and you would probably get wacked over the head by mechanics at landing, but if you absolutely must...Try this at FLAPS 10 if wind permits. Disengage the overboost stop and drive thrust levers into the limiter (you should see ENG FADEC ALTN lvl2 alerts), and stand on the brakes until the N1 is 80 or so, then let go. After taking off, have the FO monitor the retraction speeds closely and pull flaps expeditiously as soon as you reach each respective speed. Put the thrust back into normal range once clear of obstacles and put the overboost stop back where it belongs and engage autothrust. Could also try getting up into the air with Flaps 0, Slats extended.But once again, MD-11 is not designed for full-load takeoffs at such altitudes.

Just tried it - it IS possible to raise a fully loaded MD-11F cargo (would you think I'd try that on a plane with 400+ passengers? :( ) from SLLP with 75K lbs of fuel needed to make it to SEQU with FAA reserves... albeit tricky and unsafe. I found SIBUS4 departure from RWY28 to be the most forgiving.Flaps 10 or 11 work nicely, if you stand on the brakes and kick the throttles into overboost, but you reeeeeeeeally have to take all of the runway, and rotate somewhere between V1 and Vr, or even at V1 (with bad wind). Even then, you glide at a few hundred feet above the ground for a mile before gaining enough speed to climb.Also, works best if you put all paks and bleeds to manual off and cabin press to manual (close the outflow!), and re-enable them only after you've done your initial climb-out to 18000.This route is also anal in a way that you need to dump some of your reserves before SEQU to avoid an overweight landing and an obligatory maintenance checkup that follows every instance of such landing. PACTO.RNAV arrival onto RWY17 is a fun (and very hectic) experience on an overloaded MD-11. For comparison with the topicstarter, the Take Off Configuration:MD-11F- Load: Full - Fuel: 74.5K lbs- TOGW: 534.3K lbs- OAT: +18°C- Flap: 10- QNH: 10.68 inHg (1039 hPa)- Cabin Alt: 13390 (in red) - Cabin Press Sys: Manual with closed outflowAlerts:CAB PRES SYS MANAIR SYS 1-2-3 OFFAIR SYS MANUALAVNCS FAN OVRDENG1-2-3 FADEC ALTN (during overboost use)ENG1-2-3 RPM HI (during takeoff run and initial climb, as RPM goes past 112%)

Disengage the overboost stop

How do you do this?

On the real aircraft you push the throttle full forward through a gate, a bit like TOGA on a Airbus. In the sim assign overboost to your throttle or a spare key.As mentioned you should never need to use the overboost, it's only for emergencies when it's better to cook the engines then crash.

On the real aircraft you push the throttle full forward through a gate, a bit like TOGA on a Airbus. In the sim assign overboost to your throttle or a spare key.As mentioned you should never need to use the overboost, it's only for emergencies when it's better to cook the engines then crash.

Thanks, that's helpful. But I guess I won't need this when I don't fly near or at MTOW but something a little more "reasonable", will I?My other question: what should I do with cabin pressure? Surely I need to manually intervene, and above I read that I need to close the overflow valve. Question then is: when do I put it back to automatic? Will pressure become "normal" on its own during the flight, and then, once normal, I put everything on Automatic?Thanks in advance for any hints.

Moataz,this issue was raised by me a long while back while attempting a T/O from the very same airport using a Centurion freighter.Due to the very thin air at that particular no real life aircraft such as the MD-11,747,or 767 land or take-off from there.In fact,in real life,there is an American Airlines 757 that does fly in to that airport,but on take-off does not load its full route fuel so that it can lift off.It then does a short hop to some nearby airport where it re-tops up its fuel for the remainder of its journey.When I tried it with my Centurion freighter,even using a high FLEX,I could barely get it to clear the mountain range right at the end of the runway.Hope this helps.

On the real aircraft you push the throttle full forward through a gate, a bit like TOGA on a Airbus. In the sim assign overboost to your throttle or a spare key.As mentioned you should never need to use the overboost, it's only for emergencies when it's better to cook the engines then crash.

Actually, it's a bit more than TOGA on the Bus. TOGA would be the equivalent of the gate on the MD.

Due to the very thin air at that particular no real life aircraft such as the MD-11,747,or 767 land or take-off from there.

Lufthansa flew to La Paz with a 747-200, until some time in the 1980s I think. However, the next/previous stop was Lima, thus flights were not at MTOW