Seems all airlines are quite different in flap settings, in the Martinair video the Cpt says they always use flaps 25 except some flights where a optium setting may be warrented. Other sources I had read they always use flaps 15.

hi there,The more flaps you add the more drag the aircraft generates.A large flap setting will let you take off in lesser speeds with less runway and is good for clearing immediate obstacles but will downgrade climb capabilities and overall performance in case of engine failure on takeoff, so the lesser setting will usually suite better.Usually there would be a predetermined setting influenced by company policies regarding noise abatement, economics and other performance variables tailored for the specific airport (taking in to account AC weights and meteorological conditions of course).Basically the charts are there to warn of to little flaps not the other way aroundBut also to provide the pilot with operational options, In the end the pilot chooses what he feels fits the situation best. This aircraft really has the most ridicules but versatile flap/slat system, reminds a lot of the older generation up/down switch type flaps (-;Yahav lipinski

Gave it all a try yesterday.Info:Airport LFPG @ altitude 334ftrwy 08L 13000ft long.QNH 1006hPa5kts headwind174 TOGWPacks offOutside temp was 24cUsed the Excel sheet with workbook "Rws longer than 12000ft"Since 334ft elevation is <2000ft I used the sea-level diagram.Used weight 396.800lbs/180.000kgs which gave me Flex 70 with flaps 13Subtracted 3 for airport altitde (used 400ft)Subtracted 3 for Pressure (1006hPa)Added 3 for headwind (5kts)Result was a flex of 67During take-off the plane actually took off by itself instead of me having to pull back the yoke.This doesn't seem right, does it??

During take-off the plane actually took off by itself instead of me having to pull back the yoke.This doesn't seem right, does it??

Hi Eric, I recreated your scenario and performed the take-off myself.Your calculation of AT was right, according to the chart and Utopia 67C is correct.I loaded my plane with 1/3 pax and 72.500 lbs of fuel. TOGW was 396.724 lbs. Calculated V-speeds were: V1 134, Vr 142 & V2 159 knots. Thrust 100.9 and trim 5.0.I

Hi Eric, I recreated your scenario and performed the take-off myself.Your calculation of AT was right, according to the chart and Utopia 67C is correct.I loaded my plane with 1/3 pax and 72.500 lbs of fuel. TOGW was 396.724 lbs. Calculated V-speeds were: V1 134, Vr 142 & V2 159 knots. Thrust 100.9 and trim 5.0.I'm sorry, but lift-off didn't happen by itself; it still required me pulling back the yoke (although not much). Initial pitch was 15 degrees, later increasing to 20 to stay at V2+10.Are you sure you've set up everything correctly including all weights and CG's?

Yup,Had a cargo flight wich was random loaded. Used 17.000kgs of fuel. I always write down the ZFW, ZFGCG, TOGW & TOCG. FMS was programmed except the TOCG 'cause I always let the MD-11 calculate it in the 3rd MFD. That turned out to be 23.1 (as I recall correctly).I'll try and give it another go this evening to see what happens then. Already glad to know that my 67c was correct :(

Hi, EricTake into account 396.800lbs is a very light takeoff weight, about 100 tons lighter then max takeoff weight.What you describe is not necessarily an over powered takeoff (Under calculated assumed temperature) .I'll explain: There is a limit to the amount of thrust the pilot is allowed to derate from the max takeoff thrust setting (let's say 25%). Under some conditions (long runway\ low takeoff weight) the available thrust even when cut by 25% is still more then enough to get us off the ground safely (that’s a good thing!) this does not mean we cannot predict the aircraft's behavior.So instead off reducing power even more which simply takes us out off the aircraft documented safe operating envelope, we predict a shorter takeoff run with slower (usually) takeoff speeds and an incredibly cool climb profile (:The unpredictable behavior you describe is probably due to Wrong trim setting and/or CG out of Aft limits or high Vspeeds (late rotation). When exceeding the required takeoff run wile still accelerating the aircraft will get airborne eventually.I would check trim setting (check FMS takeoff page) and loading. The MD11 is usually loaded with in a pretty low MAC% range (forward CG) Also, did you use Bryan's calculated general V speeds or the FMS calculated speeds? Yahav Lipinski

Sounds to me like some incorrect trimming (maybe forgot to input the correct TOCG?), this used to happen to me before after the first update. Eric you have installed the second update? (vers 1.20)

24c and a guesstimated dew of 15c would give a density altitude of 1700 FT, would it not?If the OAT was closer to the actual air temp for Paris yesterday (24F with a dew of 10f), the density altitude would be -1700 FTwith the caculated flex being closer to 70 @ flaps 13?I'm posting this for my own tuition.Thanx,Ken

Correct!24 degrees Celsius, 1006 millibar, altitude 334 feet = density altitude 1655 feet.24 degrees Fahrenheit, 1006 millibar, altitude 334 feet = density altitude -1790 feet.In both cases AT would still be 67C as this is the maximum AT for this altitude at these conditions.

Sounds to me like some incorrect trimming (maybe forgot to input the correct TOCG?), this used to happen to me before after the first update. Eric you have installed the second update? (vers 1.20)

No, trimming isn't the issue. Like I said...I entered everything correctly in the FMS. Trying to take off without correct trimming will result in ######ing Betty complaining about the trim.I have the figures here from yesterday's flight.ZFW: 159.5ZFWCG: 18.3TOGW: 175.8TOCG: 23.317.000kg fuelI used the FMS calculated speeds, but can't recall what they where.Anyway: I'm going to recreate the flight again in a few hours and will post my results (tomorrow I guess). And yes...I'm using the latest patch/update :( Another question...I can't seem to find the information on Jeppesen charts about the slope of a runway. In the FMS, where one inputs the temp and wind direction, you can also enter the slope of a runway (the tutorial uses 0/0 there). I know that from what I recall from EHAM, rwy 27/9 is slightly sloped. Perhaps the beginning of rwy 24 too. I guess that's what needs to be put into the FMC, but...where to find that particular info? :(

All rwys in MS flight sims are flat and have no slope at all, even if the real runways do (very common), so 0 is always used.

Anyway: I'm going to recreate the flight again in a few hours and will post my results (tomorrow I guess). And yes...I'm using the latest patch/update :(

Please do so!

Another question...I can't seem to find the information on Jeppesen charts about the slope of a runway. In the FMS, where one inputs the temp and wind direction, you can also enter the slope of a runway (the tutorial uses 0/0 there). I know that from what I recall from EHAM, rwy 27/9 is slightly sloped. Perhaps the beginning of rwy 24 too. I guess that's what needs to be put into the FMC, but...where to find that particular info? :(

Don't even bother: in FS all runways are perfectly level!

:( I'm lost. I don't understand why the AT wouldn't allow me to use the "minimum" thrust (70c) under the above mentioned conditions. When using a calculated density altitude below 0 why is it I don't use "0" on the sea level correction chart ....or more to the point, why is the actual airport altitude even relevant when making the corrections?If I'm coming accross as "way lost", I'd understand why you don't post a response. :-)Ken

Correct!24 degrees Celsius, 1006 millibar, altitude 334 feet = density altitude 1655 feet.24 degrees Fahrenheit, 1006 millibar, altitude 334 feet = density altitude -1790 feet.In both cases AT would still be 67C as this is the maximum AT for this altitude at these conditions.

:( I'm lost. I don't understand why the AT wouldn't allow me to use the "minimum" thrust (70c) under the above mentioned conditions. When using a calculated density altitude below 0 why is it I don't use "0" on the sea level correction chart ....or more to the point, why is the actual airport altitude even relevant when making the corrections?If I'm coming accross as "way lost", I'd understand why you don't post a response. :-)Ken

Hi Kan,An assumed temperature is a performance number only.Using the information from the ADC(Air Data Computer) the FADEC(basically a computerized system that controls the engines) will downgrade the engine thrust setting to simulate the performance at for example a altitude of 0ft(sea level) with a assumed temperature of 67c. So if the air is extremely cold and pressure is extremely high the FADEC will simply reduce thrust further to simulate what the engine thrust output would have been with 67c at sea level(as long as total thrust reduction is not more then 20%).In extremely favorable conditions the crew can select an alternate power setting (TO2) that would derate the takeoff thrust by 20% giving them the minimum thrust allowed.In some conditions like the one you mentioned, the lowest thrust allowed is still much more then the thrust needed(for example lightly loaded on a typical winter morning at JFK 31L)Anyway, that excess thrust is great in case some thing goes wrong and it can with the PMDG simulation :(Hope that helped.Hey Bryan did you by any chance try the high altitude charts yet?Hopefully I'll give them ago this weekend, I was thinking Quito Ecuador (SEQU) 9228ft. lets put the oxygen masks on and hope for the best :( Yahav

:( I'm lost. I don't understand why the AT wouldn't allow me to use the "minimum" thrust (70c) under the above mentioned conditions. When using a calculated density altitude below 0 why is it I don't use "0" on the sea level correction chart ....or more to the point, why is the actual airport altitude even relevant when making the corrections?If I'm coming accross as "way lost", I'd understand why you don't post a response. :-)Ken

Hi Ken, I forwarded your question to Ian Webber, the author of Utopia. The maximum AT at 334 feet altitude under favorable conditions is 69C. I think I know why this is but I don

Thanx guys.I'm glad I asked.Ken