Hi there,

I’ve never had this problem in FSX/P3D before, but I’m having a hard time following the T7 flight director (all 777 models). I find myself chasing it but it feels rather jumpy/abrupt, and once I finally captured it to my satisfaction, I’m of course chasing the next waypoint and/or altitude.

I’m not sure if trimming is an issue, or  maybe it’s the sensitivity settings of my TCA Boeing yoke. I tried several different settings but with the same unsatisfactory results. 

Any tips would be greatly appreciated. 

Cheers,

Pete

This is an issue with all of their products.

Also, and this might be related - PMDG 777 (all variants) have very poor FBW/flight model. Unfortunately, it's unlikely they will ever fix it. They haven't even acknowledged the problem.

Edited July 19, 2025Jul 19 by RNAVV19R

I was just trying a flight out with the new update myself, I was cruising at FL380 when I was instructed I could Climb to FL410.

I dialed in the new altitude and clicked the altitude knob and the plane got into a perpetual pitch confusing and just started pitching up then down and back up basically porpoising.

I haven't flown it on MSFS yet, but on P3D it used to be a bit bugged in that regard. Apparently the FBW on the pitch channel wasn't well modelled, which created issues in trimming as well. In addition to that the airspeed amber band wasn't well simulated either.

I switch between MSFS 2020 and P3dv5 all the time and own the PMDG 777 in both (as well as FSL 3xx series /747 pmdg in p3d and 737 in msfs). 

The 'experience' drop between PMDG planes in p3d and msfs is disappointing to put it mildly. Don't own 2024 for the record. 

5 hours ago, sultanofswing said:

dialed in the new altitude and clicked the altitude knob and the plane got into a perpetual pitch confusing and just started pitching up then down and back up basically porpoising.

Similar example I've seen climbing to max cruise level. From say fl310 to fl340 we'll be realistically climbing at 500fpm when fully loaded then from fl340 to fl 360 the plane will suddenly climb at 2000fpm until level off. Makes no sense at all. You could argue oh you've obviously hit a thermal in msfs but only the pmdg does this. 

Following a departure to transition level also requires constant manual trimming which shouldn't be needed? 

3 hours ago, sloppysmusic said:

I switch between MSFS 2020 and P3dv5 all the time and own the PMDG 777 in both (as well as FSL 3xx series /747 pmdg in p3d and 737 in msfs). 

The 'experience' drop between PMDG planes in p3d and msfs is disappointing to put it mildly. Don't own 2024 for the record. 

Similar example I've seen climbing to max cruise level. From say fl310 to fl340 we'll be realistically climbing at 500fpm when fully loaded then from fl340 to fl 360 the plane will suddenly climb at 2000fpm until level off. Makes no sense at all. You could argue oh you've obviously hit a thermal in msfs but only the pmdg does this. 

Following a departure to transition level also requires constant manual trimming which shouldn't be needed? 

Did you recalculate the new flight level TOC in the FMC?

16 hours ago, Peter Z KCLE_EDDN said:

Hi there,

I’ve never had this problem in FSX/P3D before, but I’m having a hard time following the T7 flight director (all 777 models). I find myself chasing it but it feels rather jumpy/abrupt, and once I finally captured it to my satisfaction, I’m of course chasing the next waypoint and/or altitude.

I’m not sure if trimming is an issue, or  maybe it’s the sensitivity settings of my TCA Boeing yoke. I tried several different settings but with the same unsatisfactory results. 

Any tips would be greatly appreciated. 

Cheers,

Pete

 

Hey Pete,

You are not trying to trim for pitch are you? Just a thought.

The 777 trim works very differently to a conventional aircraft. In the 777 you trim for speed rather than pitch. It is really tempting to trim like a regular pitch trim and get in trouble. Doing so will lead to oscillations as the aircraft hunts for the speed.

The 777 you set the trim for the currently flown speed. Adjusting the trim is telling the system that you are changing speed and the aircraft will pitch around looking for that speed.

In the real aircraft you can tell by the control forces on the yoke if you are trimmed for the speed you are flying. We don't have that luxury in the sim, but there is a setting in the FMC to show a marker on the speed tape for the speed you are selecting when you trim.

So be really careful (it is easily done!) not to think you are trimming to set a pitch, when in reality you are trimming to tell the aircraft what speed you want rather than pitch.

So for example, if you disconnect from an autopilot ILS, you are already in trim for that speed courtesy of the autopilot and will manually raise and lower the nose to stay on profile, not retrim which will just have the aircraft pitch to accelerate or decelerate the aircraft using gravity, pulling the nose up to slow down or pushing the nose down if you are pitching for a faster speed.

 

hope that helps a bit

Jane

 

 

Edited July 19, 2025Jul 19 by JaneRachel

6 hours ago, sloppysmusic said:

I switch between MSFS 2020 and P3dv5 all the time and own the PMDG 777 in both (as well as FSL 3xx series /747 pmdg in p3d and 737 in msfs). 

The 'experience' drop between PMDG planes in p3d and msfs is disappointing to put it mildly. Don't own 2024 for the record. 

Similar example I've seen climbing to max cruise level. From say fl310 to fl340 we'll be realistically climbing at 500fpm when fully loaded then from fl340 to fl 360 the plane will suddenly climb at 2000fpm until level off. Makes no sense at all. You could argue oh you've obviously hit a thermal in msfs but only the pmdg does this. 

Following a departure to transition level also requires constant manual trimming which shouldn't be needed? 

hey Russell

It might be you seeing the new VNAV in action that they modelled. It is very different to a VNAV on the 737 for example. The "intelligent" VNAV on the 777 can see spurts of climb rate if the aircraft thinks it can "get away with it" . It is the same on the descent with a much more variable VNAV descent calculation than the 737 or other Boeings.

This was something that was added for 2020 and 2024 in the sim and was not around in P3D. It now more closely resembles the real VNAV which bounces around quite a bit on the 777. It is supposed to result in smarter energy management.

The 787 shares this VNAV so I think @jon b might be much better at describing it than me 🙂

 

Jane

14 hours ago, RNAVV19R said:

This is an issue with all of their products.

 PMDG 777 (all variants) have very poor FBW/flight model. Unfortunately, it's unlikely they will ever fix it. They haven't even acknowledged the problem.

Unfortunately, your assumptions are correct. When they released the first 777, at that time, I was sent from the 747 to fly the airplane for a period of time. They were provided with full documentation and a few video clips that showed exactly how their interpretation and implementation were incorrect. Interestingly, or disappointingly, the programming is correct, except for how their flight characteristics behave. Totally wrong! 

More upsetting is copying the same issues over from FSX, P3D, MSFS2020, and now MSFS2024. Granted, many people are unaware of what they are looking at; they are misled in the forum into believing that it is correct, or simply argue that it is normal, even though they have never flown a real airplane or something similar. The same applies to their problems with the FD, AP, LNAV, and other issues. Too bad.  

 

1 hour ago, JaneRachel said:

It now more closely resembles the real VNAV which bounces around quite a bit on the 777. It is supposed to result in smarter energy management.

The 787 shares this VNAV so I think @jon b might be much better at describing it than me 🙂

 

Jane

Absolutely not. 

As a previously qualified pilot in the 777, I can share with you that when you start a climb or descent in VNAV or during a SID or STAR, and there is no interference from ATC, it works very well, and it never "bounces around quite a bit". The only time when it will get behind and needs pilot intervention is when you are delayed or passed top of descent and we are behind schedule, and as a pilot, you need to intervene. It sounds more like their excuse; it does not "resemble the real VNAV". The 777 and 787 don't share the same VNAV logic. 

8 hours ago, Bigmack said:

Did you recalculate the new flight level TOC in the FMC?

WHAT new TOC?? I'm talking about doing a NORMAL climb not a step or increase during climb.

Take off, climb to level decided on ground before take off and plane speeds up climb rate last 2000ft against laws of physics OR previous climb rate was poorly calculated.

4 hours ago, JaneRachel said:

It might be you seeing the new VNAV in action that they modelled

Just saw this thx for suggestion. Well yes VNAV is supposed to do calculations on the fly especially with wind changes for example. But a heavy plane struggling to climb to initial cruise level before burning off fuel for a step climb shouldn't be able surely to suddenly (that's some alliteration there!)be able to climb at a much higher rate? Like from 500fpm for 15 mins then suddenly 2000fpm in thin air? I've even seen 3500fpm sometimes for the last 2 thousand feet.

7 hours ago, JaneRachel said:

 

Hey Pete,

You are not trying to trim for pitch are you? Just a thought.

The 777 trim works very differently to a conventional aircraft. In the 777 you trim for speed rather than pitch. It is really tempting to trim like a regular pitch trim and get in trouble. Doing so will lead to oscillations as the aircraft hunts for the speed.

The 777 you set the trim for the currently flown speed. Adjusting the trim is telling the system that you are changing speed and the aircraft will pitch around looking for that speed.

In the real aircraft you can tell by the control forces on the yoke if you are trimmed for the speed you are flying. We don't have that luxury in the sim, but there is a setting in the FMC to show a marker on the speed tape for the speed you are selecting when you trim.

So be really careful (it is easily done!) not to think you are trimming to set a pitch, when in reality you are trimming to tell the aircraft what speed you want rather than pitch.

So for example, if you disconnect from an autopilot ILS, you are already in trim for that speed courtesy of the autopilot and will manually raise and lower the nose to stay on profile, not retrim which will just have the aircraft pitch to accelerate or decelerate the aircraft using gravity, pulling the nose up to slow down or pushing the nose down if you are pitching for a faster speed.

 

hope that helps a bit

Jane

 

 

Correct, trim for speed not pitch.  The option to enable the speed tape marker can be found in FMC | PMDG SETUP | OPTIONS | SIMULATION.  The option is SHOW FBW TRIM REF SPEED.

Edited July 19, 2025Jul 19 by zachlog

3 hours ago, sloppysmusic said:

Like from 500fpm for 15 mins then suddenly 2000fpm in thin air? I've even seen 3500fpm sometimes for the last 2 thousand feet.

Unfortunately, there are serious VNAV computation bugs with respect to jumping from 500 ft/min suddenly to 2,000 ft/min. Now, if the airplane is empty and changes altitude, let's say 2,000 ft, you will most likely see an initial high ROC followed by a correction. During RVSM (low altitude separation) while small step climbing, we prefer to use VS to avoid this kind of ROC/ROD and prevent unnecessary TA or even RA situations.

 

Some additional information here to clarify this speed trim mystery and disinformation.

Primary pitch trim is controlled by the dual pitch trim switches on each control wheel. Both switches must be moved to command trim changes. primary pitch trim switches are inhibited when the autopilot is engaged. trim does not move the control column.

In the normal mode, primary pitch trim operates differently on the ground than it does in flight. On the ground, the stabilizer is directly positioned when the pilot uses the pitch trim switches. In flight, the pitch trim switches do not position the stabilizer directly; they provide inputs to change the trim reference speed. The trim reference speed is the speed at which the airplane would stabilize if there were no control column inputs. Once the control column forces are trimmed to zero, the airplane maintains a constant speed with no column inputs. Thrust changes result in a relatively constant indicated airspeed climb or descent, with no trim inputs needed unless airspeed changes.

When pilot trim inputs are made, the PFCs analyze the command and generate signals to move the elevators to achieve the trim change, then moves the stabilizer to streamline the elevator. Stabilizer motion may also automatically occur to streamline the stabilizer and elevator for thrust and configuration changes.

In the normal mode, airplane pitch control characteristics are like conventional airplanes. Unlike conventional airplanes, the control column does not directly position the elevator in flight. The control column commands the PFCs to generate a pitch maneuver. The PFCs automatically position the elevator and the stabilizer to generate the commanded maneuver.

The PFCs constantly monitor airplane response to pilot commands and reposition the elevator and stabilizer to carry out these commands. 

Airplane pitch responses to thrust changes, gear configuration changes, and turbulence are automatically minimized by PFC control surface commands.

The PFCs also provide compensation for flap and speedbrake configuration changes, and turns up to 30° of bank. The PFCs automatically control pitch to maintain a relatively constant flight path. This eliminates the need for the pilot to make control column inputs to compensate for these factors. For turns up to 30° of bank, the pilot does not need to add additional column back pressure to maintain altitude. For turns of more than 30° of bank, the pilot does need to add column back pressure.

When the autopilot is not engaged, as airspeed changes, the pitch control system provides conventional pitch characteristics by requiring the pilot to make control column inputs or trim changes to maintain a constant flight path.

Manual trim is necessary only when changing airspeed. Manual trim is not necessary when changing configuration.

Edited July 20, 2025Jul 20 by LRBS

15 hours ago, sloppysmusic said:

I switch between MSFS 2020 and P3dv5 all the time and own the PMDG 777 in both (as well as FSL 3xx series /747 pmdg in p3d and 737 in msfs). 

The 'experience' drop between PMDG planes in p3d and msfs is disappointing to put it mildly. Don't own 2024 for the record. 

...

I've used it thru the P3D days, and in 2020 and now 2024. I see only progress, the new sim offers new ways to be awed by this great beast of a plane, I love the walk around, older sims couldn't give you that sense of size like this can. I see no reason whatsoever to be "disappointed".  The flights I've flown in 2024 have been a thing of beauty!

Ever see Monty Python's Life of Brian, the classic stoning scene, simmers in these forums remind me of the women there... always so ready to stone someone 😉