Hi PMDG flyers, Need a little help on this:In a VNAV descent I receive a DRAG REQUIRED CDU message.Must I keep deployed the spoilers while the DRAG REQUIRED message is visible, and stow the spoilers when the message go out?Or must I administrate the spoilers (deploy-stow) for keep the ND Descent Guide pointer centered?Which method is correct?Thanks for help.Dirk Trotteyn (SANT)

When you see the message, bring the spoilers to the flight position until the message goes away, by which time the aircraft has slow or is on the right profile and you can stow the spoilers again.

[P CLASS=style1] Matthew Murray [/P][P][sPAN CLASS=style1]-|www.precisionmanuals.com|-[bR][/sPAN]

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AlsoAbove airport restriction (usually 10000 feet) you can allow your speed to increase to just below the barberpole while descending. You will get the "DRAG REQUIRED" message anyway but VNAV will not disengage until a couple of knots below Vmo or Mmo. When below 10000 feet you will have to be more active with your speed management as the VNAV tolerance will be narrower.Hope it helps,

Hi Dirk,Keep an eye on how far off the profile you are. IRL we would not really be using spoliers unless it is absolutely necessary as the craete vibration and noise which means uncomfortable pax.If you have not put valid wind information in the DES FORECAST page or the winds are incorrect you may find that you are off profile (either low or high) Generally the easiset way to fix being high on profile if you are far enough out (say more than 30nm) is to go to LVL CHG and increase speed for a while. Don't be afraid of this know.. if you are going to use it then USE it.. if TGT DES SPEED was 300kts then wind it up to 330 or so. This way you will regain your profile because the faster you go the more induced drag you have and this will absorb the extra enegry you have.Note:A VNAV PATH profile is FMC calculated to give you a Flight Idle Descent from CRZ ALT at your selected DES SPEED all the way to the ground.In reality we are not so much managing a DES PATH but an Energy State. The E state of the airframe consists of two components, Kinetic Energy and Potential Energy or better called Speed and Altitude. If your E state is higher than ideal you will see the Speed increasing on the PFD while the FMC tries to mainatin the path, once it gets more than 10kts above the TGT DES SPD the you get the DRAG REQUIRED message.This help?

Hi Matthew, Matts and Brad,Thanks very much for your fast and very complete responses.I received not just a help, but a real MASTER lesson from all you.Regards.Dirk Trotteyn (SANT)