LSAS Help

[JHepburn 0]

So, I've read through the manual a few times and done some test flights, but I still don't fully understand LSAS.I feel like I'm most likely fighting it when hand flying, but the problem is I'm not sure what to expect. Can someone outline what LSAS provides? 1. Should I expect to roll to any bank angle up to 30 and neutralize the yoke to hold the angle?2. What should I expect in terms of auto trim? i.e. only in level flight? throughout all bank angles?3. Should changes in trim due to autotrim display on the SD?4. Is autotrim slow to react? i.e. should I expect to be manually trimming?5. When rolling (at any rate), should I expect to have to stop the roll input with by deflecting the ailerons in the opposite direction? Feels like a lot of inertia, but other quality addons don't do this...I just don't have a real-world frame of reference to compare to.Any tips for hand-flying and how best to handle this beast would be helpful. I've been practicing which has definitely helped but still feel I'm missing something. Thanks!

[Tabs 2,790]

LSAS has nothing to do with bank angle or roll. It's purely related to pitch attitude. This is NOT Airbus style FBW.

[downscc 1,327]

Adding to Ryan's response, you have to adjust pitch in bank just like most aircraft (this is not "automatic"). The LSAS stabilizes the pitch attitude but you are still flying the airplane. Most importantly, don't overcontrol and fly smoothly as if you have paying passengers.

[JHepburn 0]

LSAS has nothing to do with bank angle or roll. It's purely related to pitch attitude. This is NOT Airbus style FBW.

Thanks Ryan/Dan,Sorry, I was thinking about Roll CWS which is mentioned in the manual as well. Is this modelled on the PMDG bird (the manual says "if installed").With regards to LSAS, lets talk technique. --Should I expect to trim once to neutral and then LSAS will maintain attitude?--Should I expect to re-trim with a power setting change if I want to keep the same attitude?--Is neutral force (i..e zero force) what the FCC looks for to autotrim, or does it look for the yoke being held steady (i.e constant force) and then autotrim does its thing to neutralize the yoke.I realize its not an airbus, but my problem is that I don't understand the operational capabilities.Thanks!

[Check_Airman 3]

I think you're over-thinking the LSAS a bit. Just fly it like it's another plane. Douglas only introduced LSAS to help with the decreased stability caused by the much smaller horizontal stabilizer on the MD11. From what I recall, if the control column force is under 2lb, LSAS will move the stab to trim off the force. Now I've read where many European pilots talk about applying so many pounds of force to the control column, and for the life of me I can't figure out how they estimate those numbers.The RCWS will maintain the bank angle selected up to 30 degrees. In the pitch axis, you still need the trim, but during approach, the LSAS will trim out small pitch changes (~1 degree), but you must be in trim to begin with. Thus, the MD is fairly stable in smooth air.I've never really tested the trim changes during flap and thrust changes, but I suspect it'll be conventional. I think of the MD11 flight controls as the half way point between the Airbus logic (g-load and roll rate) and Boeing logic (conventional control).

[JHepburn 0]

I think you're over-thinking the LSAS a bit. Just fly it like it's another plane. Douglas only introduced LSAS to help with the decreased stability caused by the much smaller horizontal stabilizer on the MD11. From what I recall, if the control column force is under 2lb, LSAS will move the stab to trim off the force. Now I've read where many European pilots talk about applying so many pounds of force to the control column, and for the life of me I can't figure out how they estimate those numbers.The RCWS will maintain the bank angle selected up to 30 degrees. In the pitch axis, you still need the trim, but during approach, the LSAS will trim out small pitch changes (~1 degree), but you must be in trim to begin with. Thus, the MD is fairly stable in smooth air.I've never really tested the trim changes during flap and thrust changes, but I suspect it'll be conventional. I think of the MD11 flight controls as the half way point between the Airbus logic (g-load and roll rate) and Boeing logic (conventional control).

Thanks Check,I'm glad you're around these parts (and the Level-D forums). As always, a great help.

[markadeane 272]

Any tips for hand-flying and how best to handle this beast would be helpful. I've been practicing which has definitely helped but still feel I'm missing something. Thanks!

Some of the beta team were discussing this recently. For the approach, a good piece of advice that came out of the discussion was to make small, individual adjustments, and wait to see how it affects the aircraft before making another. The term "bump 'n' nudge" was used to describe it.You can switch on the flightpath vector to get an indication on the PFD of your trajectory, from there it's just a case of making small adjustments to match your flight path angle to that of an optimal approach (normally -3 degrees)Lately I've found myself handflying most of the STAR just because it's so darn easy and fun!

[Dicko 3]

Some of the beta team were discussing this recently. For the approach, a good piece of advice that came out of the discussion was to make small, individual adjustments, and wait to see how it affects the aircraft before making another. The term "bump 'n' nudge" was used to describe it.You can switch on the flightpath vector to get an indication on the PFD of your trajectory, from there it's just a case of making small adjustments to match your flight path angle to that of an optimal approach (normally -3 degrees)Lately I've found myself handflying most of the STAR just because it's so darn easy and fun!

What is the flightpath vector and how do you turn it on?

[FLEX1978 373]

What is the flightpath vector and how do you turn it on?

It's in the docs but push the button above the V/S indicator on the glareshield.Rob

[Dicko 3]

It's in the docs but push the button above the V/S indicator on the glareshield.Rob

FPA?

[mpetr 0]

FPA = Flight Path Angle, so yes, that's what you're looking for.

[Dicko 3]

FPA = Flight Path Angle, so yes, that's what you're looking for.

Thanks mate

[markadeane 272]

Thanks mate

Sorry Andrew, I wasn't very clear in my explanation: Pressing the FPA button allows you to select a Flight Path Angle instead of a Vertical Speed, it also causes the Flight Path Vector to display on the Primary Flight Display, this is the little airplane symbol that shows the direction of the airplane's flight.Apologies for the lack of clarity!

[Dicko 3]

Sorry Andrew, I wasn't very clear in my explanation: Pressing the FPA button allows you to select a Flight Path Angle instead of a Vertical Speed, it also causes the Flight Path Vector to display on the Primary Flight Display, this is the little airplane symbol that shows the direction of the airplane's flight.Apologies for the lack of clarity!

No worries!

[JHepburn 0]

LSAS has nothing to do with bank angle or roll. It's purely related to pitch attitude. This is NOT Airbus style FBW.

Ryan/Dan,Sorry to dredge this old thread up, but I think I've solved my issue with LSAS not working. Does LSAS work if controllers are piped through FSUIPC?I setup my yoke directly through FS9 interface (rather than FSUIPC configuration/calibration) and all works perfectly. Autotrim maintains pitch with configuration and power changes where it didn't before!!If this only works through FS9 interface, then you guys should consider a wiki or readme entry. Thanks again for the help!!