some thoughts and questions from an avid FF user

[Bernardo_Gui]

hi

first of all, i thought i believed i was an avid boeing user, because in the past 3-4 years on xplane, the only aircrafts i used to fly (and still do) were the "other" boeings from that other very popular developer that is out there and i thought i have learned enough to be familiar with boeing style FMS, i always start my flights from cold and dark and i do fully program the FMS manually.

after having purchased this new B737 from IXEG and flew it for a few weeks, i can admit that i was blown away with the level of quality and immersion but as well there are many other surprising things that i have never experienced before, those are mostly the way how Vnav and Vapp are interpreted by the FMS in this new aircraft, i don't know if i was doing something wrong or not respecting standard procedures, but here are a few questions:

-in order to have the correct Vnav mode calculated by the FMS and then fly the flightplan with the Vnav mode engaged, why there is a need to fully program the flightplan by including the DEPARTURE and ARRIVAL runways (DEP/ARR with SID and STAR) page before activating and executing the route and even starting taxiing ? is it the way how it works irl or is it specific to the way how was modeled this FMS?

I have observed that if the departure and arrival runways are not set before activating and executing the route that is fully programmed with correct LEGs etc (and proceeding further into the PERF/takeoff page), once inflight, when the A/P is engaged the Vnav becomes not available.

Asking that because, in the other boeings, i always used to program, ACTIVATE & EXECUTE a flight plan/route without entering the dep/arr runways without sid and stars, and this before taxiing and taking off. Because i presumed that the active take off rwy is given by the atc once you are cleared to start up and allowed to taxi to that active rwy, and then only when u got that info , u enter the departure rwy & sid in the FMS and activate/exec it again to have the Vnav mode recalculated properly, but in this case, in this FMS it seems to me that it doesn't work that way.

So my experience with the 737 FMS is different. Have i ve been misled flying FF's boeings and believed what i was doing on the FMS was right, need I learn again and change my whole FMS programming procedural habit?

Can someone explain the correct FMS flight plan programming procedure then?

The other question i have is after a small short flight form EHAM to LFPG i did lately, when i was approaching LFPG, i have decided to change the arrival rwy and star proceedure to another one (compared to the one  i have set as different one previously before taking off) , after pressing activate and exec, as result (while being inflight) i got a totally erratic and irrelevant Vnav descent altitudes and approach speeds in the FMS, i have then decided to manually do the descent on the MCP instead of engaging the Vnav, also the Vapp speeds that were displayed were like 30deg flap / 577kts , the question is  why is that?  isnt the FMS supposed to recalculate the Vnav descent with the new rwy & star procedure i have just entered in the FMS? what i was doing wrong?

 

FMS bizarre Vnav screenshot

 

looking forward for further missing features to be added and other improvements into this amazing and promising aircraft.

 

thanks

 

Edited June 5, 2016 by Bernardo_Gui

[sizziano]

Every issue you describe are bugs IIRC. 

[Bernardo_Gui]

6 minutes ago, sizziano said:

Every issue you describe are bugs IIRC. 

Glad to hear these issues are 'bugs' and , hopefully those are temporary and strictly specific to the current version of this new aircraft (v1.05).

Because i believe everything i have described, even being as not very standard procedural FMS flight plan programming, the results i have experienced and exposed regarding the Vnav calculations given by the FMS are definitely not following a certain logic. This makes me think that this FMS, as it was programmed and modeled, at this moment, is not freely 'redundant' but must obey to a certain 'procedural framework and envelope' flightplan and performance programming according to what you must carefully enter in it.

 

[sizziano]

Glad to hear these issues are 'bugs' and , hopefully those are temporary and strictly specific to the current version of this new aircraft (v1.05).

Because i believe everything i have described, even being as not very standard procedural FMS flight plan programming, the results i have experienced and exposed regarding the Vnav calculations given by the FMS are definitely not following a certain logic. This makes me think that this FMS, as it was programmed and modeled, at this moment, is not freely 'redundant' but must obey to a certain 'procedural framework and envelope' flightplan and performance programming according to what you must carefully enter in it.

 

Yes. The FMC is still a WIP especially VMAV.

[chadryan]

I haven't been using VNAV as there are still some bugs. I find three TOD is almost always too close to the airport. I do look forward to the bugs being worked out.

[Litjan]

Hello Bernardo,

thanks for the feedback!

we are looking into allowing VNAV to work for climb and cruise even if there is no valid E/D waypoint in the route - the FMS won´t be able to calculate a descent, but using VNAV for the other part should be possible. It is customary procedure for most airlines to always enter the expected approach and runway while still on the ground, this way the FMS will give you more accurate predictions - and then change the STAR and approach later on, if necessary. I think flying without this entered is one of those "simmerisms" that Cpt. Randazzo is talking about, but we will probably cater to it, nonetheless (I am not even sure if it works in the real aircraft, I have never tried it in 16 years of flying Boeings...).

The descent calculations are still buggy, and Tom will be working on them shortly - there are some more pressing issues to take care of, first, though.

As for your approach speeds being way off - I don´t know who put a weight of 315.900 lbs (or kg?) into the FMS, but for that weight, I would consider 577 kts appropriate .

That being said, we should probably reject values this high, and I will forward that as an enhancement request to avoid user error to Tom.

Jan

 

Edited June 6, 2016 by Litjan

[capto]

I usually program flightplan without star and arr runway, i watch at charts altitude of the last waypoint, p.e:

LEMD SID PINAR UN870 PONEN UT600 CASPE STAR LEBL

in the 3 stars of LEBL (1,2,3) chart determine FL25 ot 26 at CASPE, i put that alt restriction and sid  n DEPARTURE runway and vnav is totally avalaible. When u are close to T/D (in case that ur cruise level is above that alt rest) u can input star and arrival without extrange altitude resuts.

hope it helps

Enrique

[jailer]

While it may be more realistic to input the departure runway and arrival from the get-go, the source of 99% of my issues with the FMS are when changing the arrival route or dep/arr runways.  Until this can be safely done without messing up the legs -- or worse, a Gizmo soft crash -- I think it's better to forgo VNAV and E/D calculations.  After all, the PROG page is still a WIP too, so you're not really missing out on much, such as fuel predictions, etc.  

Much safer to leave it TBD and inputting later than having it crash and not being able to input waypoints, go direct-to, etc.

[Litjan]

11 hours ago, jailer said:

While it may be more realistic to input the departure runway and arrival from the get-go, the source of 99% of my issues with the FMS are when changing the arrival route or dep/arr runways.  Until this can be safely done without messing up the legs -- or worse, a Gizmo soft crash -- I think it's better to forgo VNAV and E/D calculations.  After all, the PROG page is still a WIP too, so you're not really missing out on much, such as fuel predictions, etc.  

Much safer to leave it TBD and inputting later than having it crash and not being able to input waypoints, go direct-to, etc.

Yes, I see what you are saying - but you would help us with reporting the crashes, instead of avoiding them - also, a lot of those "changing STAR" and "changing approach" crash issues have been resolved, so you might be stepping around mines that are not there, anymore .

Jan

 

[jailer]

7 hours ago, Litjan said:

Yes, I see what you are saying - but you would help us with reporting the crashes, instead of avoiding them - also, a lot of those "changing STAR" and "changing approach" crash issues have been resolved, so you might be stepping around mines that are not there, anymore .

Jan

 

Absolutely.  (And I've reported my share, including recently. )  It's just that sometimes I'm in the mood where I just want to get a flight done with no possible mishaps.  There's been a marked improvement from the initial release, no doubt.

[Bernardo_Gui]

right..  

since i have updated to v1.07 and did a bit more of flights lately, the Vnav seemed to be a bit better,  but still there is something that i find bizarre regarding the DESCENT speeds and generally the descent management. When the a/c starts descending in Vnav mode (after the MCP altitude has been reset), i find really curious the way how the speed is being maintained.  Are the speeds that are displayed on each legs page  ie "294 / FL180A" are being applied during descent or it is generally overridden by the speed that are set in the 'DES' page ? Should i always manually 'confirm' the sppeds by writting 294 / and press 'exec' button for each legs? 

Because when i have let the Vnav do the descent on its own, i have noticed that i have 'overshoot' several times (different flights/approaches) the intercept localizer fix/wpt (just before aligning on the rwy/final)  and that even by applying speedbrakes,  that is because i was either too fast and even sometimes too high so i could not properly align to the localizer neither acquire a suitable descent attitude in order to engage the approach/landing mode on the G/S, that resulted in either doing a lousy/awkward fully manual/visual landing or simply approach and landing abortion and then redo the approach again.  

When i tried to tamper by manually entering the speeds in DES page (while still being in Vnav), after pressing EXEC,  i had an incoherent 'UNABLE ALT.. BLALA' message without much changing the speeds or sometimes even a Gizmo softcrash.  I have noticed that it was impossible overriding the Vnav descent speeds of the FMC by simply pressing 'SPEED' button on the MCP and adjust the desired speed there while still continuing the descent with Vnav engaged (as i find it so handy and it is possible to do in the FF's 7xx's), is this procedure technically specific to the B737 Classic or.. a bug ?

Also, another unacceptable bug that happened very recently (v1.07):  when flying past the last WPT on a route (without a STAR and arrival rwy)  instead of displaying 'END OF ROUTE' message, there was a Gizmo crash which resulted in a total loss of the FMC itself (Vnav & Lnav), as i was at FL280 i had to pursue the flight fully manually (on the MCP) .. seeing this on an aircraft like that was really gross. 

And another thing that i find really annoying, since everything in Xplane looks much better at dawn and night and thats when i prefer to fly,  please INCREASE the taxi lights intensity!  I'm still speaking as to what i used to have in other boeings by FF;  in poorly lit airports or taxiways, on the current version of the B737 even by turning on all three landing lights, taxi lights and wing lights, you still just can't see crap in front of you! the way remains dark, thats really awful and not realistic, it is done much better in other boeings by FF,  please check that out and do something about it. 

other than this, i'm enjoying flying this aircraft,   i regret certain missing details such as mousewheel button manipulator and missing wing flex of the external 3d model (at touch down and bumpy rnwy/taxiing) - interior cabin & seats would be a cherry on the cake. 

 

hopefully everything will improve with time,

 

thanks

 

 

Edited June 29, 2016 by Bernardo_Gui

[Litjan]

5 hours ago, Bernardo_Gui said:

And another thing that i find really annoying, since everything in Xplane looks much better at dawn and night and thats when i prefer to fly,  please INCREASE the taxi lights intensity!  I'm still speaking as to what i used to have in other boeings by FF;  in poorly lit airports or taxiways, on the current version of the B737 even by turning on all three landing lights, taxi lights and wing lights, you still just can't see crap in front of you! the way remains dark, thats really awful and not realistic, it is done much better in other boeings by FF,  please check that out and do something about it. 

 

Thank you for your feedback about the VNAV performance. We are still tuning it and hope to improve it, although I do read a fair amount of user misconception about how it is supposed to work in your post.

About the claim of the light intensity not being correct - may I ask you how many hours you have in real Boeing airliners? Just to confirm the credibility of your claim, of course.

Thank you very much, Jan

 

[Morten]

16 hours ago, Bernardo_Gui said:

I'm still speaking as to what i used to have in other boeings by FF;  in poorly lit airports or taxiways, on the current version of the B737 even by turning on all three landing lights, taxi lights and wing lights, you still just can't see crap in front of you! the way remains dark, thats really awful and not realistic, it is done much better in other boeings by FF,  please check that out and do something about it. 

Bernardo, what you are *used* to in in other products does not mean it is realistic.  Please do some research and document your claims if you "demand" something fixed. That said, Jan had a hard time convincing me about how poorly the lights (especially the taxi light) in real illuminate, but after seeing dozens of video's etc I agreed with him.  If anything, we set our lights on the strong side 

Edited June 30, 2016 by Morten

[mmerelles]

18 hours ago, Bernardo_Gui said:

 

When i tried to tamper by manually entering the speeds in DES page (while still being in Vnav), after pressing EXEC,  i had an incoherent 'UNABLE ALT.. BLALA' message without much changing the speeds or sometimes even a Gizmo softcrash.  I have noticed that it was impossible overriding the Vnav descent speeds of the FMC by simply pressing 'SPEED' button on the MCP and adjust the desired speed there while still continuing the descent with Vnav engaged (as i find it so handy and it is possible to do in the FF's 7xx's), is this procedure technically specific to the B737 Classic or.. a bug ?

VANV SPEED intervention (to command the speed via mcp while in vnav mode) is not supported on this simulated 733 classic avionics. Every aircraft even on same variants may have different avionics releases and updates.

While you are descending in VNAV mode the aircraft will follow whatever speeds are on the legs page. You can edit them there by entering on the scratchpad XXX/ + pressing corresponding RSK

 

That being said you have to account the following considerations:

-These jets are -very- slippery on nature, they have to be efficient on thrust and fuel burnt after all. They require planning for the descends because you can not slow down them on a dime at high speeds.

-Wind descend forecast are not implemented yet (but confirmed to be coming), the fmc calculates the descend profile based on no wind condition. Any tail wind during the flight will put the fmc in trouble to make the aircraft descend under the profile because the fmc did not expect winds pushing the aircraft forward and increasing ground speed. You have to keep monitoring the descend profile on the ND information (vertical diamond indication on the right down ND corner) and applying as much speed brakes as required to help the aircraft stay under speeding control. If you let it overshoot the profile by a big margin you will not recover from this situation easily and a chain of overshoots will follow. Remember the slippery design thing!

Applying speed brakes is a standard common technique on real life. Once you have winds forecast in place for the fmc being able to predict a more accurate descend profile you will use them less. But you will still use them.

-You have also to consider most of the arrival procedures does not establish any speeding restriction other than the FMC restricting VNAV <250 knots below 10000ft. If you look at the legs page will not see 220 200 180 or whatever, you may see 240 for all of the waypoints. This doesn't mean you can approach 240knots to intercept an ILS or to make the final pattern turns to get the runway aligned. On real life ATC will keep asking you reduce speed to, reduce speed to. And you also have to account for maximum speeds closer to XX NM to the field.

Botton line is, if you do not plan your approach having the proper background the STAR procedure will not restrict you necessarily and you will find yourself at ridiculous high speeds closing to the airport.

-if you want to control speeding via MCP you have to switch to FLCH or VS mode.

 

hope this helps a bit.

Edited June 30, 2016 by mmerelles
misspelling

[Bernardo_Gui]

2 hours ago, mmerelles said:

VANV SPEED intervention (to command the speed via mcp while in vnav mode) is not supported on this simulated 733 classic avionics. Every aircraft even on same variants may have different avionics releases and updates.

While you are descending in VNAV mode the aircraft will follow whatever speeds are on the legs page. You can edit them there by entering on the scratchpad XXX/ + pressing corresponding RSK

 

That being said you have to account the following considerations:

-These jets are -very- slippery on nature, they have to be efficient on thrust and fuel burnt after all. They require planning for the descends because you can not slow down them on a dime at high speeds.

-Wind descend forecast are not implemented yet (but confirmed to be coming), the fmc calculates the descend profile based on no wind condition. Any tail wind during the flight will put the fmc in trouble to make the aircraft descend under the profile because the fmc did not expect winds pushing the aircraft forward and increasing ground speed. You have to keep monitoring the descend profile on the ND information (vertical diamond indication on the right down ND corner) and applying as much speed brakes as required to help the aircraft stay under speeding control. If you let it overshoot the profile by a big margin you will not recover from this situation easily and a chain of overshoots will follow. Remember the slippery design thing!

Applying speed brakes is a standard common technique on real life. Once you have winds forecast in place for the fmc being able to predict a more accurate descend profile you will use them less. But you will still use them.

-You have also to consider most of the arrival procedures does not establish any speeding restriction other than the FMC restricting VNAV <250 knots below 10000ft. If you look at the legs page will not see 220 200 180 or whatever, you may see 240 for all of the waypoints. This doesn't mean you can approach 240knots to intercept an ILS or to make the final pattern turns to get the runway aligned. On real life ATC will keep asking you reduce speed to, reduce speed to. And you also have to account for maximum speeds closer to XX NM to the field.

Botton line is, if you do not plan your approach having the proper background the STAR procedure will not restrict you necessarily and you will find yourself at ridiculous high speeds closing to the airport.

-if you want to control speeding via MCP you have to switch to FLCH or VS mode.

 

hope this helps a bit.

thank you very much for clarifying this up, it reflects pretty much of what i have expected ... since this aircraft brings in more simulated features, with every new situation i discover and learn to more newer things than i used to have in other products, i believe i will need to revisit my descent management procedures and habits i used to have and this is what makes this aircraft amazing 

Edited June 30, 2016 by Bernardo_Gui