Hello,I have a question and I do apologize if it was asked before or as I think it's sillyUpon arrival and while slowing the plane down from 280K to 245K I get on the MFD, at the air speed Info, to the left green marks mentioning SE, F15, F28, F35 as I slow the plane down with a GW of 420,000LPS, those speeds usually are 275K, 240K, 220K (at a calm weather, maybe not 100% accurate), however by checking the MCDU, TO APP pages I get much lower speeds shown as a minimums of 200K Clean, 166K SE, 159 F15, 154F28 MIN, I am sure that the TO APP page refer to min. speeds that the plan would stall if the flaps setting is not applied and I should follow the speeds on the MFD, is that correct ?Sorry againAlaa Riad

Hello,I have a question and I do apologize if it was asked before or as I think it's sillyUpon arrival and while slowing the plane down from 280K to 245K I get on the MFD, at the air speed Info, to the left green marks mentioning SE, F15, F28, F35 as I slow the plane down with a GW of 420,000LPS, those speeds usually are 275K, 240K, 220K (at a calm weather, maybe not 100% accurate), however by checking the MCDU, TO APP pages I get much lower speeds shown as a minimums of 200K Clean, 166K SE, 159 F15, 154F28 MIN, I am sure that the TO APP page refer to min. speeds that the plan would stall if the flaps setting is not applied and I should follow the speeds on the MFD, is that correct ?Sorry againAlaa Riad

Hi Alaa, there is no need to be sorry, this is a support forum, that's why we're here! No question is silly provided you've described it well and signed your name to the post (both of which you have done!)Unless Markus or Robert or Ryan can advise us beforehand, I'll check on this for you when I next fly the MD11 (hopefully tonight). I'm 95% sure the figures on the MCDU are dynamic and change according to your weight, but this is only from memory.In the meanwhile, the safe and effective technique is to deploy flaps and slats at or below the 'SE' 'GE' 'F15' and 'F28' speeds on the PFD.

Heavier weights, higher speeds as mentioned. I believe the differences in the speeds you see, versus those on the speed tape are because the speed tape is showing the maximum speeds and the other speeds depicted are minimums on the TO APP page. I'd have to check on that though.

Heavier weights, higher speeds as mentioned. I believe the differences in the speeds you see, versus those on the speed tape are because the speed tape is showing the maximum speeds and the other speeds depicted are minimums on the TO APP page. I'd have to check on that though.

I believe this to be correct as well, the speed tape displays the maximum speed each flap increment may be extended while the MCDU TO/APPR page show the minimum safe speed for each flap setting.

Kyle and Shane have identified the issue here I think. Obviously you gents are better 'details men' than I am! :( The MCDU figures are minimum safe speeds for the various configurations. The marks on the PFD speed tape are the maximum speeds.

Thank you gentlemen for your needed help and support

Alaa,just so that you know, the minimum manoeuvring speeds shown in the MCDU APPR Page do NOT show the stall speed (meaning you'd stall if you'd drop 1kt below), but the minimum speed for operation for that configuration. Stall speed is way below that. On the PFD's speed tape you see a yellow bar starting at the minimum speed (Vmin), being in that yellow band does not stall the aircraft. Then at the beginning of the RED band you have the stick shaker speed (Vss), at which you still don't stall since Vss is Stall Speed times 1.1 to 1.15. But be aware that Vmin and Vss not only vary because of flaps configuration, but also because of factors like g-load and bank angle.Hope this helps!Markus

Thanks Markus, that was very educational.