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Guest Bpilot

Drag required

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Hello, Captains,At times, when descending in VNAV, the FMC informs that "DRAG (is)REQUIRED", because of too high speed.What to do? Just press > and raise the speed brakes? In real airplanes, I don't think this is a normal procedure, since abnormal changes in attitude can cause serious body damages.Any info is quite welcomed.BPilot

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Absolutely normal procedure. What abnormal attitude changes are you thinking of? Sure, you'll get a little buffeting, but nothing dangerous.....Cheers,S

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You can either use the speedbrakes or the gear to slow down ;)

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Drag Required is a message only seen when the VNAV PTH is unable to be maintained by teh AFDS whilst keeping within 10 knots of the preselected DES SPEED on the DES page. On the NG it is seen quite often and unless the speed is getting way too high then it will probably be ignored if there is plenty of distance to run, say 40 miles or greater. Another option to correct the PATH is to go to LVL CHG and crank up the speed for a while. You will recapture teh PATH and then re-engage VNAV. Using a higher speed means more induced drag and so you blow some excess E nto the airstream.. not efficient but nor is SPD BRAKE.Rgds,

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If you go with LVL CHG and crank up the speed, you

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You are not allowed to use the gear to slow down, at least that's my understanding.David

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I was just on a flight that used gear to hold speed. We were quite a ways out and I saw the spoilers up and heard the gear go down. After landing I asked the pilot and he said he had to make a steep descent because ATC kept us up higher longer because of traffic. So yeah, using the rubber airbrakes is quite alright.Tim Dobrowolsky

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Thanks, Tim,I always had the impression that using gear was a FS only trick, since in my many, many thousands of miles flown (as a passenger) through 5 continents and 44 countries, it never happened.To live is to learn...Regards from Brazil,BPilot

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huh, Stephen - I really really hope you are aware of Brads, shall we say 'qualifications' to speak on this subject.

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