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

[downscc 1,327]

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

[Guest Totalbeginner]

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

[ahinterl 1]

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

[downscc 1,327]

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

[ahinterl 1]

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

[Andydigital 93]

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.

[Guest]

• 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?

[Paul_Smith 92]

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.

[ahinterl 1]

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

[Andydigital 93]

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) :(

[ahinterl 1]

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

Andy, you're fooling me, aren't you? In the same phrase that you use you say that the maximum flaps extension speeds are "on the opposite side of the tape" just to say "the figures may not actually be written on the tape" immediately afterwards!Do you read what I write? You tell me that I'm wrong in saying the flaps extension speeds aren't on the tape just to state yourself that they're indeed not there! Very logical...

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.

Again: I know that, you may not believe it! Please re-read my previous posts.

If you don't get it now then please shoot yourself as you are clearly beyond help (joke) :(

Good to see you amused. But 1) your previous statement about the FE flags were wrong and 2) you didn't help me any further since you don't deliver any usable information.Sorry, but I think I'm somewhere in another dimension! The question is that trivial and I tried my best to make it obvious what the problem is that I have, seems noone understand, moreover:NOBODY SO FAR COULD EXPLAIN WHAT THE POSITION AT WHICH THE FE FLAGS ARE PLACED ON THE SPEED TAPE WOULD SAY, WHAT IS THAT SPEED WHERE E.G. -F28 IS?

It's not the maneuver speed, not the speed at which the flaps must be extended, not the maximum flaps extension speed, so what else is it?

I wonder why it is so difficult to give an answer to that simple question if we have all the experts here!So, here's the question again, split in discrete steps:What the heck are the FE bugs on the speed tape, i.e.:

1) They serve as indicators if maximum flaps extension speed is exceeded - this is well known, the bugs go amber in that case

2) What does the position on the speed tape indicate where the FE bugs are placed?

I'm positive and keep on asking...Andreas

[KCA9304 0]

[[What the heck are the FE bugs on the speed tape, i.e.:1) They serve as indicators if maximum flaps extension speed is exceeded - this is well known, the bugs go amber in that case2) What does the position on the speed tape indicate where the FE bugs are placed?I'm positive and keep on asking...]]Andreas,May be this helps:Previously you refered to Placard speeds avail on other aircraft.This one has them too. (below the Gear- and near the Flap Handle)Hope it gives you a clue as to what IAS or Mach number FE , F-xx and SE speed bugs refer to.FR and SR are a different story as they are based on TOWeight.If this does not help you any further, please do some screenshots to indicate what you think is wrong in a particular flight situation.Regards,Harry

[xkoote 57]

Well let's see here. With all the various posts I'll try to write down what you mean. And my apologies for not flying the MD-11 for more than a month. So my memories could be obscured.From what I understand, the various FE bugs appear at certain conditions mentioned above. (>60 sec TO and <255 and <18000 for approach). Let's take F15 as an example. I come in slow down to 250 below 10000, my F15 bug turns green because I'm below 255 knots. But my F15 bug is not situated at the limit speeds. OK. Let's see if indeed it indicates flaps 15 manoevering. According to you it doesn't. So it is not situated at the limit speed (the colors indicat you passed that point) and it's not situated at a certain manoevering speed. So you question.........What does that particular speed mean where it IS located.I have not flown the -11 in a while, but since we do not have it in the manual, I have two ideas.1. It is calculated by the FMC as a correct speed to deploy them at. Since the FMC does everything BUT extend high lift devices, it needs to tell you where it wants you to do it. Otherwise you will screw up his calculations.2. It may be a certain fixed speed below limit (to save flap tracks) or fixed speed above the next lower limit speed to allow for steeper turns or such. This can be tested with just a few MD-11 flights and a notebook.Is this the essence of what you are trying to find out? I kind of like your post and don't wish to beat you. It's what a forum is essentially for. I'm tired of the this and that doesn't work posts. Finally something that makes me think. I have an old friend who is an MD-11 captain at Aerflot Cargo, I can send him an e-mail, see what he says.Cheers,Xander

[Guest]

Andy, you're fooling me, aren't you? In the same phrase that you use you say that the maximum flaps extension speeds are "on the opposite side of the tape" just to say "the figures may not actually be written on the tape" immediately afterwards!Do you read what I write? You tell me that I'm wrong in saying the flaps extension speeds aren't on the tape just to state yourself that they're indeed not there! Very logical...

And you aren't fooling us, are you? You really GOTTA be kidding. :( Let me try it once more... ;) Since I could only find a picture with the F50 bug, let's take that as an example.You quoted yourself:

- The F50 bug turns amber when speed is more than 175 knots

Well, here you see the F50 bug (never mind the big 3 and 4: this picture is from the tutorial):As Andydigital said the NUMBER 175 ITSELF is not WRITTEN on the speed tape (like 160 and 180 are!), but you can CLEARLY see the F50 bug is EXACTLY at 175. Right...? If you can't see that, you need new glasses. ;) The F50 will ALWAYS be there and it will move up and down with the speed tape (glued, remember?)Furthermore, your current speed (watch the position of the little white line and the magenta dot!) is 159, which is LOWER than 175, so... the F50 bug is GREEN! The F50 bug is ABOVE the little white line, hence it is green and you may extend the F50 flaps if you want to! Let me repeat: when the bug is above the current speed the bug is always GREEN!If you would accelerate so your current speed (the little white line) would be ABOVE the F50 bug and hence above 175, the bug would become AMBER. In that case (when the little white line/your speed is ABOVE the bug and you are flying too fast) don't extend the flaps.For the RETRACT bugs it works the other way around. And as you can see the SR and FR bugs are ABOVE the current speed/little white line, so they are AMBER. The would become green the moment you accelerated and they passed that little white line and would end up underneath it: then they would become green.Pardon all the repetitions but I am afraid this will never get cleared up otherwise. ;)

[ahinterl 1]

Thank you everybody for your patience. I didn't want to upset anyone, if I did please take my excuse, English is not my native language and it's always difficult to express something when I need to write in a foreign language. Anyway, I guess I have a better picture now. I'll check back and see what I get in FS and come back with a final statement of what I found.Again, thank you all for your help!Andreas