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ahinterl

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

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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

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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.

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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

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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

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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

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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.

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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

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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

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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

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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

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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?

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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

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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

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The FE28 bug indicates the highest speed that Flaps can be lowered to 28 degrees.

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Andreas I think you're trying to make things more complicated than they need to be!First of all try to forget about the way that Boeing present the flap speed schedule on the PFD, this is not the way the MD11 works! There is enough informatoin on the speed tape for you to make an informed decision on when to extend or retract the flaps.For example:I've just taken off with flaps 15. My current aispeed is below the FR marker, therefore it's showing as amber. My speed is not dangerous (in my current configuration), because I'm well above the yellow low speed buffet tape. "FR" does not signify the speed I should be flying at the current flap setting (like Boeing), instead it is the very minimum speed at which the flaps "can" be retracted, it is where you should expect the yellow tape to move up to after you retract the flaps. In the above example, I would therefore consider it safe to retract the flaps, once my KIAS has passed this marker (the point at which it changes green) by a good 10 knots. You could however leave the flaps extended until approaching the yellow high speed buffet tape. Configuration changes are left up to the pilot's discreation, there is no schedule!Regards,Martin

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The FE28 bug indicates the highest speed that Flaps can be lowered to 28 degrees.
And here's the essence where I'm uncertain. Maybe I cannot see the forest because of all the trees, maybe I'm just stupid. Please comment if I'm right or wrong with the following:
  • An amber -FE28 indicates that the maximum extension speed for flaps 28 has been exceeded. There's no mark on the speed tape what this speed is, but it's written in the manual as "hard-coded" (i.e. the speeds which are on the placard in some other planes).A green -FE28 means that speed is sufficiently low to allow for flaps 28 deployment.If I'm right with my assumptions above, as a consequence, the position at which -FE28 is is unclear (because it's not the maximum speed at which flaps 28 can be set).

Andreas

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I believe it varies with gross weight, at least I expect that to be true. Otherwise your assumptions are correct.

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Otherwise your assumptions are correct.
Very bad indeed!That means in other words: It's still unclear what the position means at which -FE28 is!Heeeeeeeeelp please!!!! Someone to the rescue???Cannot be true nobody knows!!!!!Andreas

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An amber -FE28 indicates that the maximum extension speed for flaps 28 has been exceeded.
No it doesn't mean that at all. What it is telling you is that you are currently above the safe speed to extend flaps 28 and you actually have flaps set at some lower setting like flaps 15 or less. If you were to actually extend flaps 28 while still at a speed above FE28 (amber) then the yellow over-speed zone would slide down the tape to meet at a point where FE28 is on the tape.

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  • An amber -FE28 indicates that the maximum extension speed for flaps 28 has been exceeded. There's no mark on the speed tape what this speed is, but it's written in the manual as "hard-coded" (i.e. the speeds which are on the placard in some other planes).
How do you mean, there is no mark on the speed tape...? :( The FE28 setting is glued to the speed tape and moves up and down with it. It IS a mark! The colors are just an extra feature to help you out. When the mark is underneath the current speed (meaning you are flying to fast to extract), it's amber, and when it is at or above the current speed (meaning you are flying slow enough to extract), it is green. You can ignore the colors if you want: FE28 below the current speed = do not extract yet, and FE28 above the current speed = you may extract flaps.I really don't see what the problem is, or am I missing something obvious?

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Hi Andreas,You really are making this as difficult as possible. This is not a Boeing, nor is it a Cessna. It does not matter how other plans do it, this plane does it this way. Does it help to remember that the EXTEND bugs only matter on approach, when you you will be coming in from a position of higher and faster, and you will be slowing and lowering?In that situation, the bugs appear from the bottom of the tape and rise. When they first appear, they may start amber, which informs the pilot that they could extend if they really had to, but it wouldn't be advised, (I.e. when the pilot is coming in too hot), and they turn green when they are available for normal use. As such, they are a very simple, clear and intuitive way of giving the pilot the information they need, when they need it. The pilot does not need to read a plaque of hard coded numbers (difficult in turbulence, high vibration or adverse light), compare absolute numbers, or remember arbitary limits and constraints, they simply "fly the green".In your first post, you said you didn't have current access to fs to check things out. May I suggest that if in future you have more questions along these lines, feel free to ask about them here, but when you have recieved a few answers and you still do not understand how it works, please find a way to check it out yourself on FS before you start suggesting that they are too complex, or that the manual is too vague, or that the other people here do not understand them, etc. Paul Smith.

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What it is telling you is that you are currently above the safe speed to extend flaps 28 and you actually have flaps set at some lower setting like flaps 15 or less.
Not completely correct. Excerpt from the manual:

The FE bugs (-F15, -F28, -F35, -F50) are normally green and appear only when speed is less than 255 knots and altitude is less than 18,000 feet. The bugs also appear if slats or flaps are extended and more than 60 seconds have elapses since TAKEOFF mode was exited. The FE bugs turn amber as follows:- The F15 bug turns amber when speed is more than 255 knots- The F28 bug turns amber when speed is more than 210 knots- The F35 bug turns amber when speed is more than 190 knots- The F50 bug turns amber when speed is more than 175 knots

I for my part can now imagine that this means:

- FE bugs appear when below 255 kts and below FL180- FE bugs appear 60s after TAKEOFF mode was exited and flaps or slats are extended- FE bugs turn amber at fixed speeds which look like maximum flaps extension speeds; this speed is not indicated on the speedtape

Conclusion for e.g. the F15 bug:

- F15 appears only below FL180 and speed<255 kts or 60s after exiting TAKEOFF mode with flaps or slats extended- F15 is amber when the maximum flaps extension speed is exceeded (255 kts)

To me, this means in other words:

- If F15 is amber, I'm too fast to safely extend flaps 15- F15 in amber means exceedance of maximum flaps 15 extension speed- This maximum flaps extension speed is not marked on the speed tape, only the color change of the FE bug indicates above or below this speed (that was what I meant with: "An amber -FE28 indicates that the maximum extension speed for flaps 28 has been exceeded. There's no mark on the speed tape what this speed is, but it's written in the manual as "hard-coded" (i.e. the speeds which are on the placard in some other planes)." in a previous posting)- Whenever F15 is green, I can safely extend flaps 15 (since I'm below maximum extension speed)

When the mark is underneath the current speed (meaning you are flying to fast to extract), it's amber, and when it is at or above the current speed (meaning you are flying slow enough to extract), it is green.
is completely wrong (see above).
You can ignore the colors if you want: FE28 below the current speed = do not extract yet, and FE28 above the current speed = you may extract flaps.
cannot be true as well: It's not the position of the F15 bug on the speed tape which tells me that it's safe to extend flaps 15 but the color of the F15 bug which must be green.
You really are making this as difficult as possible. This is not a Boeing, nor is it a Cessna. It does not matter how other plans do it, this plane does it this way.
In what sense do I complicate things? I only collect informations here and the outcome is that nobody so far was able to answer a question which looks simple to me.All I can see is that people think they know, but in the end their informations are either wrong (see above) or incomplete as they don't give that simple answer (see below what the question is). I know that the MD-11 is different, that's the reason I ask: Because I don't know.
When they first appear, they may start amber, which informs the pilot that they could extend if they really had to, but it wouldn't be advised, (I.e. when the pilot is coming in too hot), and they turn green when they are available for normal use. As such, they are a very simple, clear and intuitive way of giving the pilot the information they need, when they need it. The pilot does not need to read a plaque of hard coded numbers (difficult in turbulence, high vibration or adverse light), compare absolute numbers, or remember arbitary limits and constraints, they simply "fly the green".
I think I often enough said that the function of the FE bugs to serve as indicators for safe flaps extension is well understood and known. This is not the point and not the question (see below what the question is).
May I suggest that if in future you have more questions along these lines, feel free to ask about them here, but when you have recieved a few answers and you still do not understand how it works, please find a way to check it out yourself on FS before you start suggesting that they are too complex, or that the manual is too vague, or that the other people here do not understand them, etc.
When did I say things are too complex? Other people indeed don't understand the meaning of the FE bugs (read through the thread, see also above), but I didn't say they do before.And with all due respect: Your suggestion to find an answer myself if nobody else can help me cannot be meant seriously. The reason why I'm asking is that I have no other source of information and hope for someone to kick in and help me out sharing the knowledge. If I were in the position to not need anyone to lay things out for me I wouldn't post here at all, I think that's obvious. If I could help myself I'd be a supernatural being and not a little simmer.Still leaves the question (again):What does the position of -F15 indicate (i.e. where along the speedtape -F15 is glued)?Andreas

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This maximum flaps extension speed is not marked on the speed tape,
Of course it is, it's on the opposite side of the tape, the figures may not actually be written on the tape, but I sure hope a pilot of an MD-11 is smart enough to understand the scale on the speedtape and figure out what that speed actually is.My understanding is that FE and FR positions on the speedtape are dynamic and are based on Weight and CG, the FMS automatically calculates and displays the relevant dynamic figure on the speedtape.If you don't get it now then please shoot yourself as you are clearly beyond help (joke) :(

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