FMC Message - "Drag Required"

[Guest delafran]

I am in the process of following the tutorial, except I changed the flight to go from CYYZ to CYOW. The simulator just paused before the T/D, just as mentioned on page 57.When I unpaused and press VNAV, I get a warning message from FMC"Drag Required"I did a search through the PDF files and I wasn't able to find such a message.This would be a good documentation enhancement. :-)So, I assume this means that my current airspeed of 320 IAS is too fast. So I deployed the spoilers. Then I thought, how long should they be deployed? What is my target airspeed during descent?If I remember correctly, somewhere in one of the A3XX docs, they mention that the speed tape has a magenta (maybe wrong colour) upper and lower bar to indicate an optimal range during descent. I don't see such a marking on the speed tape of the T7.Suggestions anyone?ThanksMark

[Guest OneTinSoldier]

I think the 'Drag Required' message will occur depending on the criteria of your next waypoint. 320 IAS might not normally be too fast for a descent. But if your next waypoint from T/D is not very far away, and requires you to be at 250 IAS for instance, and/or if your descent is fairly steep... then the FMC is letting you know that you will not be able to slow down to the 250 IAS required at the next waypoint when you reach it unless some action is taken to slow you down prior to reaching it. So I recommend having a look at what your speed is expected to be at your next waypoint. That should give you an idea as to how long you need to keep your spoilers deployed.Really, I believe it's supposed to be considered better to be well enough ahead of a your flightplan so that you do not need to deploy spoilers to slow yourself down. In other words if you have the above situation, a waypoint with a speed restriction not far from your T/D, then you should start slowing down prior to reaching T/D... so that you do not find yourself needing to deploy spoilers.Hope that helps,Jimmy Richards

[Guest Raphouille]

Hi! The "Drag required" methode is more used to achieve the vertical flight path than airspeed.The aircraft should slow to a lower speed (eg: 250KIAS@10000ft) by varying the pitch attitude.Basically, more drag = higher descent rate (VSI) at the same airspeedBest regards,Rapha

[Guest lhcc-ch]

If this message displays on FMC, then you should deploy spoilers. It will reduce your speed, so you can maintain your V/S. But spoilers cannot win a war, so that is not the best idea to try to keep 220 kts with -5000 ft/minI usually start descent approx 20 nm before T/D. It is working on all types :)RegardsAndras NyesteIVAO LHCC-CHFC/C3

[Guest OneTinSoldier]

Yes, what Andras Nyeste suggests is a good idea. I can't remember what page it's on right now, but go to the FMC and press DES NOW 20 nm before T/D and that should help out. The thing is, ATC might not like it! But I think you can request a lower altitude before pressing DES NOW.Cheers,Jim Richards

[Guest CX330_CPA Virtual]

>If this message displays on FMC, then you should deploy>spoilers. It will reduce your speed, so you can maintain your>V/S. Not quite. If you deploy full spoilers in these conditions chances are they are going to get ripped off the wings (in real world). 777/767 pilots rutinely use flight detent to slow down before the initial descent by using marginal Speed brake extension. In our panel You can control speed brakes by dragin handle and observing effect. But frankly our airplane's own drag is usually quite enough to start slowing down at a rate of about 10-15 kts/sec when the throttles are retarded to idle.Cheers.http://smileys.smileycentral.com/cat/36/36_1_16.gifhttp://www.avsim.com/pss/banner_es.jpghttp://online.vatsimindicators.net/855693/848.png