Hello,Just one quick question: is there anyway to change the VREF value in the CDU on the APPROACH page?While in final for example, you can manually edit the VAPP by prompting any entry, but it doesnt affect the VREF as it should.The put it simply, is it possible the overwrite the VREF value in order to keep the aircraft controling the speed.The only (highly unrealistic and dangerous) trick I found was to modify the ZFW, of course it changes immediately the VREF.I know that's an horror :( so I'd prefer something more orthodox...Arnaud S

Arnaud,why would you want to change Vref instead of Vapp?Markus

Hello,Just one quick question: is there anyway to change the VREF value in the CDU on the APPROACH page?While in final for example, you can manually edit the VAPP by prompting any entry, but it doesnt affect the VREF as it should.The put it simply, is it possible the overwrite the VREF value in order to keep the aircraft controling the speed.The only (highly unrealistic and dangerous) trick I found was to modify the ZFW, of course it changes immediately the VREF.I know that's an horror :( so I'd prefer something more orthodox...Arnaud S

VREF is fixed to the aircraft weight and landing flap selection, VAPP can be changed to compensate for headwinds etc.. why would you want to lower the VREF through the FMC? that would be dangerous and illegal, if you want to lower VREF put yourself in a hold and dump fuel.Rob

The put it simply, is it possible the overwrite the VREF value in order to keep the aircraft controling the speed.Arnaud S

The plane doesn't follow the VREF speed it follows the VAPP speed, because VAPP is VREF compensated for weather and runway conditions.Kevin W.

hey Markus and guys,What do I want to change Vref instead of Vapp? Erm... most likely since I'm a dangerous pilot who is not type qualified yet :(Serioulsy, I want to find how to lower the final approach speed, when on FMS SPD mode. Even at a max zero fuel weight load and normal fuel reserves(couple of tons), I find the fa speeds to be too high, at a given wind/temp/pressure.Overwriting the Vapp in the CDU does not change anything, although I understand the aircraft follow Vapp and not Vref as I wrongly thought.The lower yellow brackets on the PFD would allow me to speed down, yet the autopilot doesnt proceed. Even if I select the speed mode on the MCP by pulling the know it wouldnt allow the plane to fly below the Vapp value.I went through the FMS manual many times, didnt find anything about this.Thanks for your input anyway :)Rgds

hey Markus and guys,What do I want to change Vref instead of Vapp? Erm... most likely since I'm a dangerous pilot who is not type qualified yet :(Serioulsy, I want to find how to lower the final approach speed, when on FMS SPD mode. Even at a max zero fuel weight load and normal fuel reserves(couple of tons), I find the fa speeds to be too high, at a given wind/temp/pressure.Overwriting the Vapp in the CDU does not change anything, although I understand the aircraft follow Vapp and not Vref as I wrongly thought.The lower yellow brackets on the PFD would allow me to speed down, yet the autopilot doesnt proceed. Even if I select the speed mode on the MCP by pulling the know it wouldnt allow the plane to fly below the Vapp value.I went through the FMS manual many times, didnt find anything about this.Thanks for your input anyway :)Rgds

The MD11 is known for having the highest VREF at MLW of any passenger jet now that concord is retired, if your flying by the numbers I don't see what the problem is. It's perfectly safe and unless your using the TSR Autobrake program you have nothing to worry about in the wet or snow/slush.Also you mention your at Max ZFW, Most flights are mid to long range, the fuel required means it's unlikely you would be at MZFW on take off. To give you an example - If I'm flying a short hop EGSS - EDDF (1 hour) I can afford to load up to MZFW due to not carrying so much fuel. Therefore on approach I will be heavy with a high VREFIf I Fly EGSS - VHHH (9-10 hours) I will be well below MZFW to accommodate all the fuel, once it's all burnt off by final approach the aircraft is going to be pretty light resulting in a low VREFRegardsRob

Even at a max zero fuel weight load and normal fuel reserves(couple of tons), I find the fa speeds to be too high, at a given wind/temp/pressure.

The speeds the FMC are giving you are not too high, it takes into account all of those factors. If you are landing with a very heavy plane you should expect the speeds to be high. One way to do a slower landing is to do a 50 flap landing, and if you want to make your own VAPP speed the formula is VREF+1/2wind+gust.Kevin W

and if you want to make your own VAPP speed the formula is VREF+1/2wind+gust.

If I'm not mistaken, the MD11 uses half the wind GREATER than 20kt. So a 16kt headwind would still only be a 5kt correction, ie. you can just use Vapp.Paul

If I'm not mistaken, the MD11 uses half the wind GREATER than 20kt. So a 16kt headwind would still only be a 5kt correction, ie. you can just use Vapp.Paul

You would only use VREF+5 if the formula gave you a number lower than VREF+5 or there's a tailwind. Min Approach Speed is VREF+5Max Approach Speed is VREF+20Kevin W.

just to add my input to this if u want to fly at a lower speed why dont u turn off the auto throttle and auto pilot and land manually than u can land at any speed u like

Well thanks for your inputs gentlemen, I guess now I showed myself as a true barbarian with the eleven :( Of course I flew manually the beast over TNCM VOR 09 quite a few time and its a real pleasure.I must have kept some habits from the 747, on which you can set whatever speed you want on the MCP no matter the operating weights nor conditions and on which even on VNAV mode you can force the speeds.