General questions about the MD-11

[1Revenger1 0]

Alright, I know that I already made a thread with one of my problems but I decided I'll just create another one and put all my questions down now.

 

Question 1: When flight planning, I have always used Simbrief and it always gave me accurate fuel values and routes I could use, but it doesn't seem to quite work the MD-11. I always to have to little fuel according the MD_11 and need to add like 50k lb of fuel to make it. Am I doing something wrong in simbrief or something?

 

Question 2: During departure, I always seem to have the problem that the MD-11 won't accelerate. Then when I put up the flaps, the speed will then go up but my MD-11 will then be in the red zone for speed and basically disconnect the auto throttle and cause a lot of issues. Am I doing something wrong here during departure?

 

Question 3: During descent I always find the MD-11 comes in generally high, and makes it really hard to keep my speed low as it tries to catch up. What could be the cause of this? It has caused issues several times as I come into final approach still at like 5000ft to 7000 ft.

 

I know these are all probably really easy and simple to resolve. I have done the basics tutorial flight that comes with the MD-11, but I still had problems with being high on approach on stuff. If you guys have any other tips that would be awesome.

[pschlute 37]

1. Are you sure your load and fuel weights are the same ? Can you give an example.

 

2. What T/O flap are you using?  Are you sure the A/T is enaged ? Post some screenshots of the various stages of takeoff/initial climb.

 

3. Any waypoint altitude restrictions on your approach? If not and you are too high you need to address that by planning ahead, and descending earlier.

[1Revenger1 0]

 

 

1. Are you sure your load and fuel weights are the same ? Can you give an example.

I would just put in the route into sim brief, not change payload at all(<-- yeah I just figured it out), and then create the flight plan to put into my sim. I also put fuel weights into the MD-11 after getting the flight plan.

 

 

 

2. What T/O flap are you using? Are you sure the A/T is enaged ? Post some screenshots of the various stages of takeoff/initial climb.

I have been using T/O flap of 22, with A/T engaged. I will try to get images later tonight or tomorrow.

 

 

 

3. Any waypoint altitude restrictions on your approach? If not and you are too high you need to address that by planning ahead, and descending earlier.

All of the approaches I have done so far have had altitude restrictions on way points, generally in the form off cross X at 10000 (not below or above). During the descent, the MD-11 commonly seems to just go above them at least by 1000-2000 ft, sometimes higher, and in my experience ignore them unless it will go below the restriction.

[pcubine 143]

put all my questions down now.

Fly Tutorial 1 and Tutorial 2. These two documents will be very helpful and answer a lot of questions you might have.

[por930 51]

 

 

I know these are all probably really easy and simple to resolve. I have done the basics tutorial flight that comes with the MD-11, but I still had problems with being high on approach on stuff.

 

Hi Avery,

 

Are you using FSX? Do you use the PMDG MD11 load manager? Do you select the AutoFlight button, so that auto throttle activates above 65% throttle movement?, and prior to take off, do you still have any messages in the green box, other than maybe hand brake?

 

As Michael said, do the two tutorials, especially the first tutorial as it is pretty basic and walks you through the aircraft set up very good. when you get this tutorial correct, onto the second. Until you get the whole flights to match the tutorials, you should remain with them.

 

For tutorial 1, If you are still over an approach waypoint higher than the tutorial, and assuming you programmed the FMC correctly, and it does not have any warnings, then you will need to provide some further details and pics of the FMC etc.

 

You can always post the issue with Simbrief regarding insufficient fuel recommendation. I think they will say make sure your weights and distances are correct as per Simbrief plan, and also the weather, especially winds and temps.

[Orlaam 306]

I can't really speak to the fuel.  I have always done very short domestic cargo hauls, and can judge pretty well.  I also have some scans of old Swissair documents posted years ago with estimates on fuel usage.  Between the FMC and other resources I can judge.  In the end, just look at your fuel page after entering the flight plan, cruise altitude, and winds to see what you'll have left and the time and distance you can go.  Pretty simple really.  It's a sim so no worry about having a little extra, it won't change much.

 

As far as departure goes, it's kinda hard to know what's going on.  I have found at times that missing one step or even going out of order on the button pressing with the FCP can screw things up.  The MD-11 is not intuitive to me like the Boeing, but I've spent more time in the Boeing.  If the MD-11 behaves poorly and does something bad, you have little choice than to disconnect the AP and hand fly.  You should do that in any aircraft but the MD-11 is odd.  I used to fly it everyday and never had problems, but now I rarely fly it and sometimes it acts up.  I have noticed that if I press Autoflight to engage the AP above acceleration height that it will decelerate and enter stall protection mode.  This makes no sense to me, since I would think flying above acceleration height would just require me to nose down and the A/T would do its job.  Pressing Autoflight should just allow the plane to continue on Prof (VNAV).  I can arm Prof on ground and NAV or HDG, but still it will stall or start to stall.  If I press Autoflight below acceleration height, somewhere below 1000 feet for example, it will stay on the climb speed and continue along normally.  If I get more time I will try and figure this stalling issue out.  I suspect it's my doing.

 

For now, try arming Prof on the ground with Nav or Hdg and press Autoflight.  Then between 400 feet or 1000 feet AGL, try pressing Autoflight to see if it still happens.  You can go higher, but acceleration height is 3,000 above airport elevation normally.  I get the feeling the PMDG does not behave properly with regard to the handling of change-over to acceleration height.  If you are following the FD and trimmed then it shouldn't matter when AP is selected.  Maybe someone else knows more.

 

Also, the speed handling of the MD-11 has always been buggy IMO.  I've had multiple overspeeds and other oddities such as the barber-pole being too low for the conditions.  It definitely doesn't like Active Sky and is extremely sensitive to minor weather changes.  On descent, unless you descend early, you will often ride the spoilers to maintain speed.  I don't recall ever being too high very much, but you will ride the spoilers for sure. 

 

I did a flight tonight just to test your issues.  I entered an altitude constraint into the descent into KEWR, VOR DQO.  FL220, hard constraint.  I was able to achieve it no problems without starting the descent early but I rode the spoilers in 2/3 position for a good bit of time to maintain speed. 

 

 

Maybe if I get more time I can help.  I just haven't flown this plane much in FSX.  I'm enjoying the NGX, Q400, and Duke now.  My time is limited too.  I do love this plane though and wish PMDG would update it.  Wouldn't take much really.

[pcubine 143]

Also, the speed handling of the MD-11 has always been buggy IMO. I've had multiple overspeeds and other oddities such as the barber-pole being too low for the conditions. It definitely doesn't like Active Sky and is extremely sensitive to minor weather changes. On descent, unless you descend early, you will often ride the spoilers to maintain speed. I don't recall ever being too high very much, but you will ride the spoilers for sure.

That's an odd paragraph to me. It just goes to show how different computers handle the same plane. I have no problems with overspeed or maintaining speed without the use of the speed brakes. And ASN causes no problems at all. ASN or FSX default clear sky all fly the same for me.

[Orlaam 306]

I noticed the FMC says FL222 at DQO for some reason. I know I entered FL220 and it shows that it crossed at FL220 so I'm unsure if selecting my approach altered that somehow after the fact. Either way...

 

If memory serves me, out of all my FMC equipped aircraft with complex systems, the Level-D seemed to do the best job hitting the altitudes preselected in the flight plan. I may be wrong, and it's been ages, but I somehow remember that. As much as I've always spent the most time in PMDG when it comes to this type of aircraft, I've always had more issues with VNAV descents in their planes. The original NG and now the NGX. To be fair the real world aircraft are notorious for being off too so it's kinda moot. I can't really compare anything since I'm not flying them real world. Perhaps the Level-D was incorrect and too forgiving.

That's an odd paragraph to me. It just goes to show how different computers handle the same plane. I have no problems with overspeed or maintaining speed without the use of the speed brakes. And ASN causes no problems at all. ASN or FSX default clear sky all fly the same for me.

Well to be fair I've never had an overspeed in FSX either, but in FS9 with Active Sky back then, it was common. I do however have to extend the spoiler on the MD during descent if I follow the preprogrammed TOD mark. It might indicate 280 knots but continue to build speed and give the ADD DRAG message every time. That is something I've had in FSX and FS9.

[pcubine 143]

It might indicate 280 knots but continue to build speed and give the ADD DRAG message every time.

I think that message appears at 286 knots if your default decent speed is 280 knots. I would say unless the speed exceeds 290 knots and continues to increase during descent, I would disregard it. It will eventually come back to 280 knots. I know this is not correct but it seems like the more you use the speed brakes the more the MD-11 depends upon you to use the speed brakes. It's like it has a mind of its own. It thinks this guy is going to use the speed brakes, so it doesn't worry about controlling the speed. Farfetched but that the way it seems.

[1Revenger1 0]

Hi Avery,

 

Are you using FSX? Do you use the PMDG MD11 load manager? Do you select the AutoFlight button, so that auto throttle activates above 65% throttle movement?, and prior to take off, do you still have any messages in the green box, other than maybe hand brake?

 

As Michael said, do the two tutorials, especially the first tutorial as it is pretty basic and walks you through the aircraft set up very good. when you get this tutorial correct, onto the second. Until you get the whole flights to match the tutorials, you should remain with them.

 

For tutorial 1, If you are still over an approach waypoint higher than the tutorial, and assuming you programmed the FMC correctly, and it does not have any warnings, then you will need to provide some further details and pics of the FMC etc.

 

You can always post the issue with Simbrief regarding insufficient fuel recommendation. I think they will say make sure your weights and distances are correct as per Simbrief plan, and also the weather, especially winds and temps.

Yes, I have been using FSX, and do select the autoflight button before takeoff, and I have no msgs in the green box. I'll try to run through the tutorial again later today.

 

I can't really speak to the fuel.  I have always done very short domestic cargo hauls, and can judge pretty well.  I also have some scans of old Swissair documents posted years ago with estimates on fuel usage.  Between the FMC and other resources I can judge.  In the end, just look at your fuel page after entering the flight plan, cruise altitude, and winds to see what you'll have left and the time and distance you can go.  Pretty simple really.  It's a sim so no worry about having a little extra, it won't change much.

 

As far as departure goes, it's kinda hard to know what's going on.  I have found at times that missing one step or even going out of order on the button pressing with the FCP can screw things up.  The MD-11 is not intuitive to me like the Boeing, but I've spent more time in the Boeing.  If the MD-11 behaves poorly and does something bad, you have little choice than to disconnect the AP and hand fly.  You should do that in any aircraft but the MD-11 is odd.  I used to fly it everyday and never had problems, but now I rarely fly it and sometimes it acts up.  I have noticed that if I press Autoflight to engage the AP above acceleration height that it will decelerate and enter stall protection mode.  This makes no sense to me, since I would think flying above acceleration height would just require me to nose down and the A/T would do its job.  Pressing Autoflight should just allow the plane to continue on Prof (VNAV).  I can arm Prof on ground and NAV or HDG, but still it will stall or start to stall.  If I press Autoflight below acceleration height, somewhere below 1000 feet for example, it will stay on the climb speed and continue along normally.  If I get more time I will try and figure this stalling issue out.  I suspect it's my doing.

 

For now, try arming Prof on the ground with Nav or Hdg and press Autoflight.  Then between 400 feet or 1000 feet AGL, try pressing Autoflight to see if it still happens.  You can go higher, but acceleration height is 3,000 above airport elevation normally.  I get the feeling the PMDG does not behave properly with regard to the handling of change-over to acceleration height.  If you are following the FD and trimmed then it shouldn't matter when AP is selected.  Maybe someone else knows more.

 

Also, the speed handling of the MD-11 has always been buggy IMO.  I've had multiple overspeeds and other oddities such as the barber-pole being too low for the conditions.  It definitely doesn't like Active Sky and is extremely sensitive to minor weather changes.  On descent, unless you descend early, you will often ride the spoilers to maintain speed.  I don't recall ever being too high very much, but you will ride the spoilers for sure. 

 

I did a flight tonight just to test your issues.  I entered an altitude constraint into the descent into KEWR, VOR DQO.  FL220, hard constraint.  I was able to achieve it no problems without starting the descent early but I rode the spoilers in 2/3 position for a good bit of time to maintain speed. 

 

 

Maybe if I get more time I can help.  I just haven't flown this plane much in FSX.  I'm enjoying the NGX, Q400, and Duke now.  My time is limited too.  I do love this plane though and wish PMDG would update it.  Wouldn't take much really.

Appreciate the help. I generally do turn on the autopilot at around 400-500 ft. I don't know if this is a factor but other than the tutorial 1 departure, all my departures are in heading mode at first and have you vectored around by ATC.

 

I have figured out the fuel issues though, it was me just not putting the pax/cargo weights into simbrief.

[1Revenger1 0]

So I am in the middle of the tutorial flight,  the first one, and it is going smoothly...I'll update this post after landing.

Quick question though, why is the tutorial so adamant about you putting the STAR through the waypoint before and not directly on the airport? Is it a case of the plane would fly over the airport then go attempt to do the STAR after passing over the airport if you did put the STAR information by clicking on the airport instead of the waypoint before?

 

After Starting Descent:

This is a complete failure... the md-11 leveled out at 20k ft even though the descent meter on the ND kept telling it to keep descending. So now at this point, I should be at below 10k ft but I am at like 15k ft.

 

After Landing:

Well, I landed. I'll start adding pictures of the descent. I have no idea why the aircraft held at 20k ft even though it quite obviously was being told to descend.

 

Hold at 20k FT:

http://prntscr.com/b4xde4

 

Startish of Descent:

http://prntscr.com/b4xdwp

 

Tell me if you need more pictures.

[pcubine 143]

After Starting Descent:

 

This is a complete failure... the md-11 leveled out at 20k ft even though the descent meter on the ND kept telling it to keep descending. So now at this point, I should be at below 10k ft but I am at like 15k ft

The PMDG MD-11 can't handle restrictions that are entered as a below altitude. What you need to do is clear BLM and then reenter BLM and see if the altitude calculated by the FMS is below 20000. If it is, you are okay. If not you may need to start the descent early so that you will be below 20000 ft. I had this trip me up on a couple of STARS into KMEM that have waypoints with altitude restriction above and below certain altitudes.

Quick question though, why is the tutorial so adamant about you putting the STAR through the waypoint before and not directly on the airport? Is it a case of the plane would fly over the airport then go attempt to do the STAR after passing over the airport if you did put the STAR information by clicking on the airport instead of the waypoint before?

I don't remember the exact problem this caused, but when I clicked on the airport, I had to clear everything that was entered by the STAR and then click on the transition prior to the airport. Everything was okay then. The route from the waypoint prior to the STAR to the airport was just like it appeared on the charts.

[pschlute 37]

You can clear the AT/BELOW altitude by pressing the RSK of the waypoint concerned. This brings up the VERT REV page. Press the CLR button, then the LSK beside the AT/BELOW restriction.

[scandinavian13 5,192]

 

 

pressing the RSK

 

If you're referring to a line select key, it's still LSK, but LSK-R#. The L isn't for directionality, it's for 'line.'

[pschlute 37]

If you're referring to a line select key, it's still LSK, but LSK-R#. The L isn't for directionality, it's for 'line.'

 

Aha, my memory isn't what it used to be.  Thanks.