Archived

This topic is now archived and is closed to further replies.

ahinterl

MD-11: Exact description of -FE and -SE bugs needed

Recommended Posts

Since I have no resources at the moment to update my previous thread:Can someone please give me an exact and thorough/extensive desctiption of the -FE and -SE speed tape bugs (no excerpts of original PMDG manual texts please, I've read through and know them well).I'm especially interested in what sense they serve as landmarks for flap extension and retraction schedule as well as their capability of serving as maneuver speeds.Andreas

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

If you have read the manuals (Systems 30.16 onwards) then you are aware that the bugs show the max speed the slats, flaps and/or gear can be safely extended. If amber, then they indicate you are too fast to safely extend. If they do not show at all, you are probably to high.

Share this post


Link to post
Share on other sites
If you have read the manuals (Systems 30.16 onwards) then you are aware that the bugs show the max speed the slats, flaps and/or gear can be safely extended. If amber, then they indicate you are too fast to safely extend. If they do not show at all, you are probably to high.
The manual says nothing about that the -FE and -SE bugs indicate the minimum speed where slats/flaps can be extended safely. Where did you read that?What the manual says about e.g. the -SE bug is:-) appears only when [slats are retracted] AND [speed is [> 220 kts when Mach is displayed] OR [> 225 kts when Mach is not displayed]]-) is amber at speeds > 280 kts (Mach 0.55) and green otherwiseNo word that -SE shows any safe speed when the bug is green as you say.I go even further and say that the manual doesn't explain what all the bugs except of the V speeds bugs exactly mean. Apart from the statement that they turn amber under certain circumstances there's no word on what the color coding itself expresses (some caution I guess) and the positioning along the speedtape means.What I see is that guesswork is done, considering "-FR" as the point where it's safe to retract flaps (=the "R" in "-FR") and -GR where the gear should come in, but I for my part didn't find any line in the manual that confirms that this guesswork is true. Same for the -FE and so bugs.If all the MD-11 simpilots here on this board don't have the faintest doubt on what these bugs exactly are it shouldn't be that difficult to give me a precise answer. Either my brain is completely twisted or there's indeed a lack of information (what I ecpect -- with my twisted brain)!Andreas

Share this post


Link to post
Share on other sites

Since many read this thread but the're no more answers, I assume either everyone is happy to not really know what the bugs are but keeps on flying even without this knowledge or the ones who know don't like to share the informations.A pity...Andreas

Share this post


Link to post
Share on other sites

The way I see it once they go green you can do what they say, i.e. retract flaps or slats. If they are amber then wait.Pretty sure that this was in the tutorial

Share this post


Link to post
Share on other sites
The way I see it once they go green you can do what they say, i.e. retract flaps or slats. If they are amber then wait.Pretty sure that this was in the tutorial
Well, that's true, but not entirely completely correct, specially in regards to take off: when FR turns green, it does not mean you can immediately retract the flaps! Only when the speeds moves up and away from FR you should retrect flaps! When FR turns green but the speed stays at about the same spot (FR can swich between amber and green a few times when the speed is sort of at the same spot as the FR sign), you should not retract flaps already! This can make a big difference!During approach you can indeed set flaps as soon as a setting becomes green, but still, it's not necessary or always wise to do so. I always wait with setting the first flap (15) until I am closing in to LOC. And even though F28 or F35 are on the PDF and green for ages, I still wait until I intercepted G/S before I set them.

Share this post


Link to post
Share on other sites

I agree in that if the FE bugs go green, speed is below maximum flaps extension speed for a given flaps setting.The big question for me is: At what discrete positions are the FE/SE/GE flags positioned on the speed tape? What do their positions indicate?If it were only for checking whether it's "safe" to extend slats/flaps/gear, it would be sufficient to have some static indications like the flaps position indicator on the PFD below the speed tape which go green and amber and are "disconnected" from and not part of the speed tape.But now that they're on the speed tape and at certain positions/speed, I guess that "means something" and they're not just "floating around" on the speed tape!I cannot figure out at what positions these flags are since some people told me they cannot be used for flaps scheduling. Scheduling e.g. the extension of flaps/slats is merely based on the maneuver speeds for the different flaps settings. So, if the MD-11 FE/SE bugs don't show maneuever speeds (and they don't according to other user's informations), what else do they indicate?Andreas

Share this post


Link to post
Share on other sites

I think it might help if you include the FMS MCDU in your scanning.In the TAKEOFF page you see the computed V speeds, V1 Vr V2 and VFR VSR and VCL.This gives you the fixed information you need to decide how you are going to configure the aircraft according to any departure constraints. The speed scale display is then intuitive - green ok, amber caution...It's the same for approach, as part of your preparation look at the MCDU APPROACH page to see CLEAN MIN, SLAT EXT MIN, FLAP 28 MIN, VAPP, VREF. Also check speeds on the GO AROUND page.Normally high lift devices are not deployed at their maximum limiting speeds, it's kinder to wait until about 20Kt above the minimum speed...Chris G

Share this post


Link to post
Share on other sites

Andreas,[[The big question for me is: At what discrete positions are the FE/SE/GE flags positioned on the speed tape? What do their positions indicate?]]FE/SE/GE are not only limited by IAS. There is also a Mach limit.That's why they are not always fixed, but may be 'floating around'.Regards,Harry

Share this post


Link to post
Share on other sites

Thank you Harry.I currently have no access to FS :( So, are the FE/SE bugs where the minimum speed for these flaps settings are?And what about the GE flag? I guess there's no minimum speed for gear extension...Andreas

Share this post


Link to post
Share on other sites

The FE/SE bugs are maximum extended speeds (not minimum).The minimum speed for gear extended is irrelavent since the gear should be out before Flaps 28, the GE bug indicates the maximum gear operation for extension.I am missing something from this thread... there is no mystery behind these speed bugs for flaps and gear. What am I missing?

Share this post


Link to post
Share on other sites

Hi Andreas, In two of your posts, you have used 'minimum' in connection with the SE, FE and GE bugs. That is simply not correct and is the probable cause of your confusion. There is no minimum speed when it is safe to EXTEND, but there is a MAXIMUM. If you are at or below the bugged speed, the bug shows green and it is safe to extend. If you are too fast, or is is otherwise not appropriate to extend, then the bug either does not show, or shows amber.That is it. There is no other complication, meaning or interpretation. If the EXTEND bug is green, it is safe to EXTEND. Paul Smith

Share this post


Link to post
Share on other sites
There is no minimum speed when it is safe to EXTEND, but there is a MAXIMUM. If you are at or below the bugged speed, the bug shows green and it is safe to extend. If you are too fast, or is is otherwise not appropriate to extend, then the bug either does not show, or shows amber.That is it. There is no other complication, meaning or interpretation. If the EXTEND bug is green, it is safe to EXTEND.
The FE/SE bugs are maximum extended speeds (not minimum).The minimum speed for gear extended is irrelavent since the gear should be out before Flaps 28, the GE bug indicates the maximum gear operation for extension.I am missing something from this thread... there is no mystery behind these speed bugs for flaps and gear. What am I missing?
OK, maybe it's not that obvious, so here again for a better clarification what I mean:1.I understand there's no minimum speed for flaps or gear setting. I expressed the wrong way. What I meant was more the minimum speed at which the plane can safely fly with a given setting (i.e. maneuver speed).Maneuver speed indications are a perfect way to decide when to extend what flaps best, i.e. it serves as a decision for flaps scheduling.Since I was told the FE/SE flags don't serve for flaps scheduling, they cannot indicate maneuver speeds.2.The flags have two functions as far as I can see:2.1.) They show that the maximum extension speed for a given flaps setting is exceeded by coloring that specific FE bug amber. This has nothing to do with the position of the flag itself along the speed tape! It's just to say "you're too fast for extending flaps xx".2.2.) The 2nd function is the meaning of the speed at which these flags are positioned on the speed tape. Since this speed is neither Vfemax for a given flaps/slats setting nor the maneuver speed, I simply ask: What speeds are these? In other words: What speed is the speed where e.g. -FE28 is positioned?As long as 2.2. is unanswered (and I have still no final answer; "FE/SE bugs are maximum extended speeds" cannot be completely correct because maximum extend speed is indicated by color=amber and not the position of the FE flag), it is a mistery for me.Andreas

Share this post


Link to post
Share on other sites