This seems not to be related specifically to PMDG Md-11 rather than a general discussion. However, i was planing a flight with the MD-11 freighter from El-Alto Intl, La Paz - Bolivia (ICAO: SLLP) with elevation of around 13300ft to Mariscal Sucre Intl, Quito - Ecuador with elevation around 9200ft.When i try to Take Off it takes barely the whole rwy to rotate, and when try to climb the plane stalls and fall eventually, Considering the rising terrain in the Take Off path.I already know that in such high altitudes we have less density air (Hot and High) so i didn't use any thrust reductions.My Take Off Configuration was as follows:- Load: Full - Fuel: 88.0 lbs- TOGW: 507.5 lbs- OAT: 8c- Flex: 9- Flap: 25- QNH: 1037- Cabin Alt: 13430 (in red) - Cabin Press Sys: Auto with open outflowAlerts: AVNCS Fan Override With all the factors above, any one have an idea on how to increase drag and lift during Take Off and climb out?How to Adjust Cabin Press with such high altitude?Thanks in advance.

Hi Moataz, Sorry but I'm not sure on the exact answer to this. But if you want max thrust then don't enter a Flex value at all. You entered 9 but that in itself is thrust reduction.

Well I don't have my real MD11 books on me right now, but according to the PMDG FCOM in the limitations section you will see an environmental envelope that shows the MD11 is not certified to takeoff or land at an airport with a pressure altitude above 10k MSL.Kevin W.

Well I don't have my real MD11 books on me right now, but according to the PMDG FCOM in the limitations section you will see an environmental envelope that shows the MD11 is not certified to takeoff or land at an airport with a pressure altitude above 10k MSL.Kevin W.

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?

Interesting question !Cross the 747 off your list (8400' according to PMDG). The airliners that I can find that get the closest are the 737NG which can work at 12,000' if equipped with a high altitude system, then the 727-100/-200 which can work to 10,000' as standard according to the DF docs. So I had a look at every SLLP picture on airliners.net. There are loads of radial engined airliners and a smattering of turboprops, the jets that have been photographed there are loads of 727s, a few 737s, a couple of a319s and a single 757.Guess what I'll be trying next time I have some time to sim !Gary

Nice one! Thank you. I just flew a freight flight from SPIM via SLS, AND, JUL to SLLP and back again, 2/3 load and about 20,000 Kgs fuel (43,000 Lbs). I had to put the air system to manual and manipulate to outflow valve to get a reasonable landing pressure (I imagine real world pilots would stay on oxygen masks during the turn around). For takeoff from SLLP, I had about 2/3 load and 19,000Kgs fuel. I used 15 flaps and no flex for a reduced drag takeoff (shallower climb but shorter roll). I did have momentory overspeed on N2 for each engine during the take off roll, peaking at 112.8% but no other difficulties.

Interesting question !Cross the 747 off your list (8400' according to PMDG). The airliners that I can find that get the closest are the 737NG which can work at 12,000' if equipped with a high altitude system, then the 727-100/-200 which can work to 10,000' as standard according to the DF docs. So I had a look at every SLLP picture on airliners.net. There are loads of radial engined airliners and a smattering of turboprops, the jets that have been photographed there are loads of 727s, a few 737s, a couple of a319s and a single 757.Guess what I'll be trying next time I have some time to sim !Gary

I guess yeah!Try and tell me which one operates good.

Nice one! Thank you. I just flew a freight flight from SPIM via SLS, AND, JUL to SLLP and back again, 2/3 load and about 20,000 Kgs fuel (43,000 Lbs). I had to put the air system to manual and manipulate to outflow valve to get a reasonable landing pressure (I imagine real world pilots would stay on oxygen masks during the turn around). For takeoff from SLLP, I had about 2/3 load and 19,000Kgs fuel. I used 15 flaps and no flex for a reduced drag takeoff (shallower climb but shorter roll). I did have momentory overspeed on N2 for each engine during the take off roll, peaking at 112.8% but no other difficulties.

I wonder in real life operations, these legs is not profitable for companies operating there unless they equip their Aircrafts with high altitudes equipments to have full aircrafts capacities.Thanks for reply anyway.

I wonder in real life operations, these legs is not profitable for companies operating there unless they equip their Aircrafts with high altitudes equipments to have full aircrafts capacities.Thanks for reply anyway.

It would not be used by this airframe for scheduled service but there is no reason why charter flights shouldn't be profitable.

I love posts like this. I don't care about real life, I have to give this a go with a heavy MD-11 asap. In my sim of course :(

Having landed a Centurion Cargo MD-11F GE from KMIA to SLLP,and having read this thread,I tried a take-off.Full load as set in the Config Manager,T/O Flex set to blank will not do.So dropped to 2/3rd load as suggested in some posts,Flex to zero,flaps to 25,fuel 60 kgs but remembered to set Altimeter to 3034 which then gives the correct altitude at SLLP,V2 to 170 and despite running N1 into red for a short while,did manage a take-off from Rwy10.Once cleared of the runway kept the climb shallow until speed settled,then onto AP,PROF,NAV,etc.Saved and then aborted the flight to input the flightplan via the FMS later.Hope this helps Moataz.RICK

You should use less flaps not more! Flaps increase drag and while they increase climb angle, they increase take off run. Less flaps means less drag, and shorter take off distance (or more weight for the same take-off distance) but also lower climb angle - only a factor in obstacle avoidance. There is an AAL 757 which does a scheduled KMIA -> SLLP and back, but if you check the small print, you will see it has a 'technical stop' after leaving SLLP. My guess would be that it takes off from SLLP with a very low fuel load and stops somewhere to top-up. Try your flight again with full load, 15 flaps and 15 ~ 20Kgs fuel (and plan a refueling stop).

You should use less flaps not more! Flaps increase drag and while they increase climb angle, they increase take off run. Less flaps means less drag, and shorter take off distance (or more weight for the same take-off distance) but also lower climb angle - only a factor in obstacle avoidance. There is an AAL 757 which does a scheduled KMIA -> SLLP and back, but if you check the small print, you will see it has a 'technical stop' after leaving SLLP. My guess would be that it takes off from SLLP with a very low fuel load and stops somewhere to top-up. Try your flight again with full load, 15 flaps and 15 ~ 20Kgs fuel (and plan a refueling stop).

Well, I tried this and it worked fine, and its much better if u r planning for a long haul trip.

You should use less flaps not more! Flaps increase drag and while they increase climb angle, they increase take off run. Less flaps means less drag, and shorter take off distance (or more weight for the same take-off distance) but also lower climb angle - only a factor in obstacle avoidance. There is an AAL 757 which does a scheduled KMIA -> SLLP and back, but if you check the small print, you will see it has a 'technical stop' after leaving SLLP. My guess would be that it takes off from SLLP with a very low fuel load and stops somewhere to top-up. Try your flight again with full load, 15 flaps and 15 ~ 20Kgs fuel (and plan a refueling stop).

Surprised no one picked up on this but your absolutely wrong, more flaps 'decreases' T/O run at the expense of a poorer climb profile. Flaps increase drag but they also increase lift giving you a lower VR, the problem is the flaps are now decreasing your climb profile due to that extra drag so it's a fine balance. It looks like your getting a little mixed up :)

Surprised no one picked up on this but your absolutely wrong, more flaps 'decreases' T/O run at the expense of a poorer climb profile. Flaps increase drag but they also increase lift giving you a lower VR, the problem is the flaps are now decreasing your climb profile due to that extra drag so it's a fine balance. It looks like your getting a little mixed up :)

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.

Flaps ..... they increase climb angle

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.