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craig_read

Speed restriction question

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>the 250 below 10000 rule is only stict towards non-heavy>aircraft. There are also smaller aircraft needing more than 250kts below FL100, an example here would be the MD-90 close to MTOW. Those will of course get hight speed as well if needed.Regards,Markus


Markus Burkhard

 

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Ok I re-read what has been put here again.. and this is my problem re-stated, I think there has been some confusion..I have for SPEED REST 250/FL100 in my FMC my SPEED TRANS is blank.. AND despite this.. while in VNAV the plane is travelling with 252 knots set on the PFD and also it's doing this BELOW FL100.. and I am SURE it should not do this.RegardsCraig


Craig Read, EGLL

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Oops, meant to put this here.. Ok I re-read what has been put here again.. and this is my problem re-stated, I think there has been some confusion..I have for SPEED REST 250/FL100 in my FMC my SPEED TRANS is blank.. AND despite this.. while in VNAV the plane is travelling with 252 knots set on the PFD and also it's doing this BELOW FL100.. and I am SURE it should not do this.RegardsCraig


Craig Read, EGLL

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>Oops, meant to put this here.. >>>Ok I re-read what has been put here again.. and this is my>problem re-stated, I think there has been some confusion..>>I have for SPEED REST 250/FL100 in my FMC my SPEED TRANS is>blank.. AND despite this.. while in VNAV the plane is>travelling with 252 knots set on the PFD and also it's doing>this BELOW FL100.. and I am SURE it should not do this.>>Regards>>Craig>>> "Technically" I am pretty sure the AFDS should stay at what you input into the SPD RES line. In practice though, another question is why would you fly in such a manner? VREF + 100 is most likely always going to be faster than 250 knots (Of course lightly loaded might not be but I have not bothered to verify) and that is what you fly at regardless of the airport restriction. Most pilots of the 744 that I have talked to about this even stated that they go to 300 knots well below 10000' and the 250/10000 rule does not apply to 744s that I am aware of. So yes I would "guess" (and notice GUESS) that it should follow the restriction under 10000'.... Best,Randy J. Smith

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"and that is what you fly at regardless of the airport restriction."You do what ATC allow. If you ask to have the airport speed limit waivered and they refuse.... then you're not going to argue, are you? :(It depends on the country... Some countries still rigidly enforce the rule. Seems that Canada and Koread do (or did):http://www.pprune.org/forums/showthread.ph...iction+10%2C000http://www.pprune.org/forums/showthread.ph...iction+10%2C000Cheers.Q>

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>10000' and the 250/10000 rule does not apply to 744s that I am>aware of.Randy,It should apply to everybody, only those that can't hold this speed because of performance limitation would typically be exempt. A fairly light 747 after a long transoceanic crossing coming for landing should have no problem in complying with this regulation. This is a practical regulation to give pilots more reaction time when they spot each other visually in class E airspace (or even in :( where there is a high probability of encountering some VFR traffic.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

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I am going by a few pilots on the beat that have stated this. If you think about it, one flys over the Pacific and there is no need to guess about lighter weights in this regard. I don't believe ATC would hold a fully loaded or heavy loaded to some airport restriction for the restriction's sake if the pilot needs to climb faster than 250 knots which still holds true for many 744s.Best,Randy J. Smith

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Real controllers don't lose too much sleep over it :-)Scott


Kendall S Mann

Still Telling Pilots Where To Go!!

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Not true! Acft that must exceed 250 for safety reasons are automatically waived. Honestly, most controllers wouldn't know the differece between 250 and 280 on departures. Arrivals are a different matter. By the time you get where you're going, you should be light enough to maintain 250.Scott


Kendall S Mann

Still Telling Pilots Where To Go!!

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Randy,We'll waive it for departures. Not arrivals. Technically, we aren't allowed to waive the 250 restriction at all. It's just understood that a fully loaded 747/DC10 and a few others will need to exceed 250 to be operated safely. I know it's in an FAR somewhere, I just don't know which one.Scott


Kendall S Mann

Still Telling Pilots Where To Go!!

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"It's just understood that a fully loaded 747/DC10 and a few others will need to exceed 250 to be operated safely. "Scott.. I don't see why it's unsafe to keep the flaps extended up to 10,000... unless, perhaps, there is icing conditions or heavy turbulence (Wing Anti-Ice can be affected by L/E flap deployment... Actually, on some 400's, WAI is inhibited during flap extension). Otherwise it's just a fuel burn issue.Craig... I tried a heavier weight in PMDG. Vref+100 was about 276kts. The speed pretty much stuck to 250kts up to 10,000' (+/-1 kt except during sudden wind changes). Everything seems to be operating normally.As Scott says, a few knots is no big deal.Cheers,Q>

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Yes.. I understand all this stuff about the speed waiver.. etc etc.. I'm well aware that speed restrictions are sometimes not imposed for large heavy aircraft.. I'm not really interested in that side of it.. so let's forget ATC completely..THIS IS.. PURELY a sim question.. WHY.. is it possible for the FMC to set my speed at 252 knots on the PFD BELOW FL100 ... when I have CLEARLY set the FMC with a SPEED REST of 250/FL100... SURELY.. it's breaking my rule! And I know 2 knots is insignificant.. but regardless.. HOW can it do it!? Surely it should not be able to do this.. It's breaking my 250 knot SPEED REST that I gave it and displaying it to me! Let me make it a bit more clear..I am NOT changing the speed, VNAV has taken over selecting speeds, the speed dial is BLANK as it should be in this case.. As I retract my flaps etc.. from the takeoff, as I would expect with VNAV in operation it increases the speed target as appropriate during the early stages of the climb. And at one point the PFD target speed set by VNAV is 250 knots.. HOWEVER.. shortly after this and I'm taking no more than 1 minute.. VNAV changes the target to 252 knots.. puts it in magenta on top left of the PFD.. it's BROKEN MY RULE! I didn't think that was possible!? Why is it doing it!? SPEED REST is 250/FL100... my speed set by VNAV is 252.. below FL100...My thoughts are.. if it's ok for it to break it now.. why not break it later?!? I thought 250/FL100 in SPEED REST was CONCRETE.. and that was it.. it would never go over 250 knots below the set FL100... and the fact is.. it's not is it.. because I've got a target of 252 set by VNAV! This my question.. this is not normal is it?If you'd like a screenshot of what I'm seeing to prove it.. I will get you one..CheersCraig


Craig Read, EGLL

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Beats me... I tried the same entries as you in PMDG's 744 and the VNAV target climb speed remained at the SPEED REST of 250kts and the speed stuck to 250kts... even though V2+100 was 252kts.Can't fault my copy of the sim. BTW, which version do you have?. I have the Freighter/update version.Cheers.Q>

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