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Guest jp

Use of speedbrakes

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Guest jp

Hi,Have been flying the 738 for quite a while now. I did however notice that the aircraft is very hard to slow down with a proper descend rate, meaning the use of speedbrakes is practically always a must here, certainly when flying on VATSIM. As many of you know, you can plan your flight in advance, but once onto the descend, changes in altitude and direction are constantly given by ATC.So far, so good, i have no problem with it, that is what they are build for. My question is if there are limits on the use of those speedbrakes.Personally I use them from IAS lower than 290 knots and when needed, down to 220 knots (not continuously of course) with flaps 2 if required. I would like to know if that procedure is correct.I ask this question because I have read somewhere that use of speedbrakes is allowed from below IAS 300 and until flaps 5. Outside those limits the use of speedbrakes would cause too much stress on the aircrafts mechanical structure.I would appreciate if somebody could confirm this statement or is it wrong? In case it is I would like to know:1. Are there limits for speedbrake use?2. What are they?Best Regards,Jean-Pierre Thirifay

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Guest B1900 Mech

This is all I found in a flight manual I have, "Per Airworthiness Directives 2001-12-51 and 2002-08-52,

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Guest jp

Hi Jim,Thank you for that fast reply. Reading your text my assumption was quite right, meaning I can continue using them for speed reduction and descend profile without wondering if i'm currently stressing the aircraft too much.Thanks again, appreciate it,Best Regards,Jean-Pierre Thirifay

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Jim,To add to your comments, flying with Radar Contact which I do on every flight since I am on the beta test team for the next version of Radar Contact, I too have had a problem, with descents. Using Flight Change, I can maitain the correct speed on descent, but I don't make the correct crossing restricting due to the distance I travel toward my final fix while making the descent.If I use V/S on the MCP of 2000FPM I can make my crossing restrictions, but I can't keep the speed at 280Knots with a descent rate of 2000fPM even with spoilers up. The problems seems worst with the -800 than it was with the -700. Yes I know that the -800 is heavier, but it seems that it "sliperer" than the -700.The question I would ask the PMDG team is the affectiveness of the spoilers is consistant with the real bird? I know that most items on this bird are right on from what I have been told by pilot friends. However the spoiler thing is troubling me. When I fly for real, I don't notice a lot of speed brakes until getting close to the final approach altitude.Any commnets would be appreciatedCheersBob Johnson

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