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Michael Moe

FBW deserves some time and learning and lots of practice

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First i must admit i am a simmer and not a pilot but i can sense the time and programming PMDG has put into this bird with latest updates on the FBW systems.

 

As i say i am mostly off scale here and trying to learn a little of the systems that it truly provides as a simmer and reflecting real world pilots.

 

So where can i start my questions - please ignore my lack of experience here :-) i am what i am. This is mostly pitchmode Questions i guess

 

I have a Saitek Yoke and have tried all sorts of combinations with the null zones and resetting both FD´s afterwards

and for now i have left them at 5% since i dont even know what the deadzones should be in the calibrating menu for my yoke.

 

I am unsure what my FMA should be in with Autopilot off using these auto functions provided by the FBW

 

Maybe same conditions as if the Autopilot is on ? :-) (from a simmers brain )

 

That leads me to FLCH . When i am at 250 knot 10000 feet (in or not in trim) and want the FBW to go to 240/5000 using FLCH the bird actually begin to raise the nose and overshooting 10000 feet

 

I set the MCP to 240 and trim ref speed to 240 ,  altitude to 5000 and hit FLCH Before pressing the yoke forwards the bird is climbing.

 

What is the normal procedure here with the autopilot off ?

 

 

 

V/S

 

I find it very very hard to have the plane folllowing a -+1000 feet as if it was in manually mode (hence the null zone i guess)

 

I dont blame the PMDG but rather my setup so please join in with settings to my yoke or just experience with teqnigues (i have seen the trim video around here but thats the problem :-) )

 

 

 

Thrust is in HOLD mode alot:

 

Which is normal i guess during a descent but i still hat A/T armed so why does the bird goes from 240 to 150 in  FLCH 230 ? . My brain says it should go in either SPD or THR mode when speed gets low and in FLCH mode ?

 

Again sorry for my lack of exp....

 

 

 

Thanks i hope i dont put to much silly questions here 

 

 

 

(A/T is  armed all the time offcause)

 

P3Dv2.5

 

Michael Moe

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What is the normal procedure here with the autopilot off ?

 

The normal procedure with autopilot off is to fly the airplane.  Forget the FBW.  It is designed to make this jumbo fly like any non-FBW equipped airplane with a few exceptions not important here.

 

The normal procedure with autopilot off depends on what you are trying to do.  The F/D is normally used as a reference for the pilot but it is not required.

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Hmm okay i guess but i am not trying to forget in this post. I am trying to learn

 

 

Also F/D recycling has more to it i guess

 

Anyway thanks

 

Michael Moe

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Also F/D recycling has more to it i guess

 

What do you mean by F/D recycling?  I am trying to help but we need to understand each other.

 

If you want to leave A/P off and hand fly, then you can do this with or without the flight director (F/D).  The F/D is a very nice tool for the pilot, say you want to hand fly an ILS but you are new to the airplane. Use the F/D to provide pitch and roll commands with the single cue or cross hair bars to guide you thorough the approach.

 

None of this has anything to do with FBW.

 

The best way to start learning this aircraft is by flying the tutorials until they become too easy for you. Be sure to have fun.

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What do you mean by F/D recycling? I am trying to help but we need to understand each other.

 

If you want to leave A/P off and hand fly, then you can do this with or without the flight director (F/D). The F/D is a very nice tool for the pilot, say you want to hand fly an ILS but you are new to the airplane. Use the F/D to provide pitch and roll commands with the single cue or cross hair bars to guide you thorough the approach.

 

None of this has anything to do with FBW.

 

The best way to start learning this aircraft is by flying the tutorials until they become too easy for you. Be sure to have fun.

 

 

Thanks

 

I guess i just meant that recycling the F/D maybe would reset any mode the AFDS was in but thats maybe only with autopilot on. I thought if i suspected that i was in a wrong pitch or roll state i could just recycle them to go in neutral mode.

 

Michael Moe

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Hmm okay i guess but i am not trying to forget in this post. I am trying to learn

 

 

Also F/D recycling has more to it i guess

 

Anyway thanks

 

Michael Moe

The thread title is very misleading. Almost nothing in your first post relates to FBW. Almost everything relates to the autopilot and its modes, which aren't any different to a non-FBW airliner.

 

Don't get too concerned about the FBW, in fact it's best to forget it is there and fly normally.

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That leads me to FLCH . When i am at 250 knot 10000 feet (in or not in trim) and want the FBW to go to 240/5000 using FLCH the bird actually begin to raise the nose and overshooting 10000 feet

 

I set the MCP to 240 and trim ref speed to 240 , altitude to 5000 and hit FLCH Before pressing the yoke forwards the bird is climbing.

 

What is the normal procedure here with the autopilot off ?

 

 

We are talking FD on and AT on, but AP off here right?

 

Ok, you are using the FBW trim ref speed all wrong.

It is NOT to be used as a target indicator......but as a REFERENCE to what the in-trim speed is.

The aircraft will search/hunt for this speed when you let go of the controls.

 

You mainly need a better understanding of what trimming does in the first place though I think, but that is a long story.

 

 

When you trim A Cessna or a B737, all you are doing is trimming the forces away that you are exercising on the yoke to keep the airplaine lever for example.

When in-trim you can let go of the yoke and the nose will stay where you put it.

When not in trim the nose will go up or down (regardless of what altitude you put in altitude selector or window) because the aircraft will start looking/hunting for its in-trim speed.

 

The same with the 777. If you put it out of trim....which is any time the FBW trim ref indicator is not EXACTLY at you CURRENT speed.....it will start hunting for its in-trim speed as well.

 

So if you are at 250kt....and then put the FBW trim ref indicator at 240kt by trimming.....then you are no longer in-trim...you are now OUT of trim!

And the nose will shoot up trying to become slower.

The AT has to be seen separately here.

They are two different system.

So although you put the AT target speed at 240kt.....you are not flying 240kt yet....it takes a little time.

But with the FBW trim ref speed out of trim by 10kts the FBW system reacts instantly and shoots up.

A Cessna would do the same if you hold the yoke, trim it out of trim, and then let go of the yoke.

 

The trim ref speed is only there as a refenrence.

The real 777 does not have this indication at all by the way. It is only provided by PMDG so that if your airplane does not want to stay where you put it, you can have a look at where the FBW trim ref speed is. And if out of trim, you can then quickly see which way to trim to get in-trim.

It is there to help you see whether you have trimmed correctly or not enough.

 

So, you are at 250kt, level in 10.000ft and the FBW trim ref speed is also at 250kt.

You could now let go of the yoke and the aircraft should be pretty stable.

Now, set traget speed from 250kt to 240kt..

The AT will reduce thrust.

With the yoke, make an effort to keep level flight (or a shallow descend if you want to descend with FLCH).

As airspeed decreases throught 249...248...247 you are now getting OUT of trim.

So hit the trim switches untill the FBW trim ref speed is at your actual speed again (so at 247 for example)

If you dont trim then the airplane will pitch down more than you want because it will search for its in trim speed which is still 250kt...if you did not trim at all.

So keep making small trim inputs just like you would with a Cessna or B737....constantly try to keep the FBW trim ref speed as close as possible to ACTUAL indicated speed.

 

You should end up after a little while with indicated speed = 240kt = FBW trim ref speed, and you can at that point let go of the yoke again and the aircraft should again be pretty stable.

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We are talking FD on and AT on, but AP off here right?

 

Ok, you are using the FBW trim ref speed all wrong.

It is NOT to be used as a target indicator......but as a REFERENCE to what the in-trim speed is.

The aircraft will search/hunt for this speed when you let go of the controls.

 

You mainly need a better understanding of what trimming does in the first place though I think, but that is a long story.

 

 

When you trim A Cessna or a B737, all you are doing is trimming the forces away that you are exercising on the yoke to keep the airplaine lever for example.

When in-trim you can let go of the yoke and the nose will stay where you put it.

When not in trim the nose will go up or down (regardless of what altitude you put in altitude selector or window) because the aircraft will start looking/hunting for its in-trim speed.

 

The same with the 777. If you put it out of trim....which is any time the FBW trim ref indicator is not EXACTLY at you CURRENT speed.....it will start hunting for its in-trim speed as well.

 

So if you are at 250kt....and then put the FBW trim ref indicator at 240kt by trimming.....then you are no longer in-trim...you are now OUT of trim!

And the nose will shoot up trying to become slower.

The AT has to be seen separately here.

They are two different system.

So although you put the AT target speed at 240kt.....you are not flying 240kt yet....it takes a little time.

But with the FBW trim ref speed out of trim by 10kts the FBW system reacts instantly and shoots up.

A Cessna would do the same if you hold the yoke, trim it out of trim, and then let go of the yoke.

 

The trim ref speed is only there as a refenrence.

The real 777 does not have this indication at all by the way. It is only provided by PMDG so that if your airplane does not want to stay where you put it, you can have a look at where the FBW trim ref speed is. And if out of trim, you can then quickly see which way to trim to get in-trim.

It is there to help you see whether you have trimmed correctly or not enough.

 

So, you are at 250kt, level in 10.000ft and the FBW trim ref speed is also at 250kt.

You could now let go of the yoke and the aircraft should be pretty stable.

Now, set traget speed from 250kt to 240kt..

The AT will reduce thrust.

With the yoke, make an effort to keep level flight (or a shallow descend if you want to descend with FLCH).

As airspeed decreases throught 249...248...247 you are now getting OUT of trim.

So hit the trim switches untill the FBW trim ref speed is at your actual speed again (so at 247 for example)

If you dont trim then the airplane will pitch down more than you want because it will search for its in trim speed which is still 250kt...if you did not trim at all.

So keep making small trim inputs just like you would with a Cessna or B737....constantly try to keep the FBW trim ref speed as close as possible to ACTUAL indicated speed.

 

You should end up after a little while with indicated speed = 240kt = FBW trim ref speed, and you can at that point let go of the yoke again and the aircraft should again be pretty stable.

Thanks for the explanations.

 

Regarding the nose up behavior it only starts when i set the trim speed in this example from 250 to 240.The plain actually levels if i let the AT decrease first with the MCp set at 240. I dont feel this behavior trying to chase the reference speed still at 250 in this example.

 

 

Yes i need to learn alot more here about the systems. I also try handflying this bird using FLCH and V/S for pitch mode and offcause here the speed has 2 different prioritys offcause.

 

I just find it hard to put pressure on the yoke maintaining +-1000 feet and let go with a new flightlevel set in the MCP offcause. The bird is all over +-1500 feet for instance like its i manually mode and therefor i could use som saitek settings the works for others. Now we are also not in trim as we might increase or decrease air speed. I guess i have use trim as well during the decent or ascent catching current speed ?

 

Must go back to the FCOM and read some more.

 

The elevators is not directty moved using the trim ref speed in the air, only on ground. Guess it meens that the force is controlled as electric inputs.

 

Will have a look on that trim video again. I really thought i was doing what he did.

 

Thanks alot for taking the time to explain.

 

Michael Moe

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I just find it hard to put pressure on the yoke maintaining +-1000 feet and let go with a new flightlevel set in the MCP offcause. The bird is all over +-1500 feet

 

My advice is to fly the tutorials. Do use the A/P and A/T systems as instructed in the tutorials. This helps you work on the understanding of systems.

 

As for handflying my recommendation is to stick to low level work at maneuvering speeds instead of cruise speeds at the flight levels. Things happen a lot faster in that thinner air and piloting requires more experience. Go out on a sunny day from your favorite airport and just fly around at 8000 ft and 230 kts and get used to the feel of level 90 deg turns and work up to climbing/descending 180 deg turns.  Learn to fly the airplane.

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Thanks i will do that. I saw the video one more time and see how i got it all wrong there.

 

Thanks again

Michael Moe

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