Selecting STAR after passing T/D results in Invalid Entry

[NBouc 54]

Hi,

After flying several flights with the PMDG B777-200 LR, I have noticed that if I don't have yet selected a STAR when reaching T/D, I am unable to do so afterwards because it results in an Invalid Entry message on the FMC. There is also no speed/altitude prediction displayed on the LEGS page for any FIX remaining past the T/D (true in both P3Dv3 and P3Dv4, on both B777 v1.10.8333.0 and v1.10.8363.0).

In the NGX with P3Dv3 (Patiently awaiting the NGX 64-bit version), I can fly past the T/D and even fly past the last FIX on the route (no STAR pre-selected and flying on HDG mode once past the last FIX), and still be able to select a STAR, set the next waypoint ahead as active, re-engage VNAV / LNAV and resume navigation on the STAR. But not so with the B777. Is it an intended limitation on the 777 or is there something I am missing ?

I am interested in knowing if I can change this behavior on the 777 because before departure, I prefer to enter the route up to the first STAR transition fix only, and wait closer to the airport to select the STAR since there are many destinations where the STAR starts so far out and selecting the right one is runway dependent but you are not yet in range of the ATIS to confirm what runway is in use (I know, I could guess it by looking at the last Wx report, but ...)

Thank you in advance to anyone having an idea on this.

[PMDG777 231]

2 hours ago, NBouc said:

Hi,

After flying several flights with the PMDG B777-200 LR, I have noticed that if I don't have yet selected a STAR when reaching T/D, I am unable to do so afterwards because it results in an Invalid Entry message on the FMC. There is also no speed/altitude prediction displayed on the LEGS page for any FIX remaining past the T/D (true in both P3Dv3 and P3Dv4, on both B777 v1.10.8333.0 and v1.10.8363.0).

Have you read the FCOM? What does it say? Do you know if the real aircraft does/does not allow this?

2 hours ago, NBouc said:

In the NGX with P3Dv3 (Patiently awaiting the NGX 64-bit version), I can fly past the T/D and even fly past the last FIX on the route (no STAR pre-selected and flying on HDG mode once past the last FIX), and still be able to select a STAR, set the next waypoint ahead as active, re-engage VNAV / LNAV and resume navigation on the STAR. But not so with the B777. Is it an intended limitation on the 777 or is there something I am missing ?

The 737 is not the 777. Completely different systems.

2 hours ago, NBouc said:

I am interested in knowing if I can change this behavior on the 777 because before departure, I prefer to enter the route up to the first STAR transition fix only, and wait closer to the airport to select the STAR since there are many destinations where the STAR starts so far out and selecting the right one is runway dependent but you are not yet in range of the ATIS to confirm what runway is in use (I know, I could guess it by looking at the last Wx report, but ...)

Change? Doubt it. If that's how it is in the actual aircraft then you cannot change it. Plus, you should have planned your arrival before your descent anyway.

[downscc 1,327]

On 6/25/2017 at 3:49 PM, NBouc said:

I am interested in knowing if I can change this behavior on the 777 because before departure, I prefer to enter the route up to the first STAR transition fix only, and wait closer to the airport to select the STAR since there are many destinations where the STAR starts so far out and selecting the right one is runway dependent but you are not yet in range of the ATIS to confirm what runway is in use (I know, I could guess it by looking at the last Wx report, but ...)

In reality, your arrival selection determines where the TOD is going to be.  You don't need to be in range of ATIS, for example using AS16 simply get your destination weather with Ctrl+F11 at anytime during the flight.

My normal procedure is to look at arrivals on long trips about 500 nm out, I anticipate which STAR is going to be used and set it up without an approach.  Just get it in there to establish the TOD.  Then 50-100 nm before TOD I do my pre-arrival checks including wx, baro, Vref, approach briefing, etc.  Any changes to the landing direction after TOD is going to pretty much rule out VNAV anyway and you'll be flying vectors and altitudes from ATC.  In reality, you're checking ATIS just before handoff to approach which is typically below 10,000 so it never has an impact on arrival selection.

[NBouc 54]

4 hours ago, downscc said:

In reality, your arrival selection determines where the TOD is going to be.  You don't need to be in range of ATIS, for example using AS16 simply get your destination weather with Ctrl+F11 at anytime during the flight.

My normal procedure is to look at arrivals on long trips about 500 nm out, I anticipate which STAR is going to be used and set it up without an approach.  Just get it in there to establish the TOD.  Then 50-100 nm before TOD I do my pre-arrival checks including wx, baro, Vref, approach briefing, etc.  Any changes to the landing direction after TOD is going to pretty much rule out VNAV anyway and you'll be flying vectors and altitudes from ATC.  In reality, you're checking ATIS just before handoff to approach which is typically below 10,000 so it never has an impact on arrival selection.

Dan,

I appreciate your point of view and the normal procedure you describe is pretty much what I normally do too. But when I feel comfortable enough with the aircraft’s systems in performing normal and well planned flights with no surprises, I like to add unexpected changes to the experience such as route change, weather avoidance deviation and last minute runway change, especially at airports I am very familiar with (things I have seen very often during my ATC career). Doing this brings me a deeper understanding of the aircraft possibilities and limitations that I don’t necessarily grab after reading the FCOMs and other manuals.

What motivated me to post on the subject is simply my surprise of not being able to modify some aspects of the automated flight past a certain point. I was not expecting that limitation and I wanted to know is it was normal with the 777 or if it was me who missed something important in my reading, because as an ATC, I never heard a 777 pilot say something like “We need radar vectors then” after I issued a modification to the runway in use just before handing him over to the approach controller, forcing him to select a different branch of the STAR (HABBS3.06L vs HABBS3.24B for example).

The reference I made in my initial post regarding the lack of speed/altitude prediction after T/D might give a wrong impression. It was the result of a test I made by voluntarily delaying the data entry in the FMC, just to see what the result would be (I was expecting a different result, obviously).

I guess I’ll just have to keep doing normal, well planned in advance and uneventful flights with the 777 ;-)

Thank you again for your point of view.

Best regards,

[PMDG777 231]

2 minutes ago, NBouc said:

What motivated me to post on the subject is simply my surprise of not being able to modify some aspects of the automated flight past a certain point. I was not expecting that limitation and I wanted to know is it was normal with the 777 or if it was me who missed something important in my reading, because as an ATC, I never heard a 777 pilot say something like “We need radar vectors then” after I issued a modification to the runway in use just before handing him over to the approach controller, forcing him to select a different branch of the STAR (HABBS3.06L vs HABBS3.24B for example).

Hi Normand,

I'm no 777 pilot so don't know for certain, but perhaps RW pilots have an expected RWY and approach entered, and change it after TOD, whereas you're trying to enter a RWY and approach after TOD? Perhaps that's the difference? Maybe you can CHANGE the approach/rwy after TOD, but you can't enter it from blank?

[NBouc 54]

1 hour ago, PMDG777 said:

Hi Normand,

I'm no 777 pilot so don't know for certain, but perhaps RW pilots have an expected RWY and approach entered, and change it after TOD, whereas you're trying to enter a RWY and approach after TOD? Perhaps that's the difference? Maybe you can CHANGE the approach/rwy after TOD, but you can't enter it from blank?

Hi Chris,

That is a possibility I haven't thought of. I'll experiment with it to see what can be achieved. I've noticed so far that as long as I enter a STAR before reaching TOD, I can later (past TOD) change the approach if it is part of the choices for that STAR, but I cannot change the STAR itself. 

For example, on a HABBS3.24B STAR, I can initially set the approach to be ILS 24R, and later change it for RNAV 24R or even ILS 24L (because of B for Both), but if the STAR says HABBS3.06L, I cannot cannot change it for HABBS3.06R. I am committed to an approach on 06L if I want the FMC to do the job.

Thank you for the idea, I'll try different things that will surely better my understanding of the 777 systems.

Best regards,

[PMDG777 231]

11 minutes ago, NBouc said:

For example, on a HABBS3.24B STAR, I can initially set the approach to be ILS 24R, and later change it for RNAV 24R or even ILS 24L (because of B for Both), but if the STAR says HABBS3.06L, I cannot cannot change it for HABBS3.06R. I am committed to an approach on 06L if I want the FMC to do the job.

Best regards,

Forgive me if I misunderstood you. I would have thought that if you changed runway in the FMC, it would reset the STAR selected and you would be able to select another STAR available for that runway? Is that not the case? Let me run that through:

You've got the FMC set up for 06L and the HABBS3.06L STAR. If you go into Dep/Arr and change the arrival runway to 06R, it keeps the HABBS3.06L STAR selected and you cannot change the STAR to HABBS3.06R?

[NBouc 54]

1 hour ago, PMDG777 said:

You've got the FMC set up for 06L and the HABBS3.06L STAR. If you go into Dep/Arr and change the arrival runway to 06R, it keeps the HABBS3.06L STAR selected and you cannot change the STAR to HABBS3.06R?

Hi Chris,

Based on the way I explained it, you understood correctly. But I found out I was not 100% correct in what I wrote. I initially thought that by not being able to change the STAR, I was committed to that runway. It did not occurred to me to try and change the approach instead of the STAR. Here's what I discovered tonight. I just flew into CYUL on the OMBRE4.24L STAR with ILS 24L selected. Past TOD, I tried to change the STAR to OMBRE4.24R and got an "Invalid entry" (So, cannot change the STAR).

But if in the ARR/DEP page I leave the STAR OMBRE4.24L alone and instead select the approach ILS 24R, it is accepted with a "route discontinuity". The fixes for the ILS 24R replace those for ILS 24L in the LEGS page (they are added at the end of the STAR itself, following the discontinuity). At that moment, I must simply decide when to leave the STAR leading to runway 24L and proceed direct the IAF for the ILS 24R (correcting the discontinuity by making the first fix for the ILS 24R active).

Edit: Forgot to mention that even after activating the ILS 24R approach, it is still impossible to change the STAR leading to 24L (Invalid entry).

It is not too bad when changing from the left side to the right side of parallel approaches, but it might be a bit more inconvenient when changing from lets say, 06L to 24R (opposite sides of the same runway). Then I need to be vectored because my only valid waypoint reference becomes the IAF for 24R.

I hope I explained myself better this time. Nonetheless, I really enjoy flying the 777. It keeps my "grey matter" active.

 

Cheers,

 

[spesimen 135]

you have to select all of the pieces of the puzzle for it to be valid. if you are trying to choose a STAR transition that is specific to a particular runway while you have a different runway selected, that doesn't work! the points in the STAR are different in this case!! this won't work on the 737 or 747 either..

simply choose all three parts - the desired runway/approach/star and it should load it up into the legs just fine, with a disco after your current route... and then you can manipulate the points in the fmc to your desire. those route discontinuities are there because it doesn't know exactly why or where you are changing things so it is up to you to manipulate them correctly by selecting up the waypoint you want to go next and removing the extra ones.

and as pointed out earlier, don't sweat it too much as it is rather unrealistic that you wouldn't know your star by the time you are nearing the TOD anyway. plus you wouldn't be able to correctly calculate the TOD without having that information or at least a good guess about it. but even if something happens where you need to change them completely there is no reason you cannot do so, just make sure all the elements are selected particularly when you are dealing with STARS that are specific to a particular runway.

good luck and happy flying!

cheers,-andy crosby

[downscc 1,327]

I flew into KIAH the other day when TS Cindy was passing by, was set up for the DOOBI arrival landing ILS26L where entry into the arrival was at AEX.  On descent but before AEX the flow switched at Houston Bush, and since this location uses different STARs for East vs West arrivals, I had to switch to GESNER and ILS08L.  I don't recall having to do anything other than close the discos and over write some of the left over DOOBI.  I don't recall precisely but I probably entered FLCH while the vertical path was being recomputed and maybe added a little thrust in HOLD to adjust.... I don't always recall the details.  This pretty much supports Andy's comments.  Had I been past AEX, I still should have been able to negotiate the changes but with a little more splicing maybe and more or less thrust to modulate the descent profile.

[NBouc 54]

16 hours ago, spesimen said:

simply choose all three parts - the desired runway/approach/star and it should load it up into the legs just fine, with a disco after your current route... and then you can manipulate the points in the fmc to your desire.

Hi Andy, doing it before reaching TOD works as intended indeed. I can change STAR and approach at will until TOD. But past TOD, the 777 won't let me (Invalid Entry when selecting a different STAR, even with the same entry point and even if the next 4 waypoints are common to both STARs).

16 hours ago, spesimen said:

don't sweat it too much as it is rather unrealistic that you wouldn't know your star by the time you are nearing the TOD anyway.

What I am trying to simulate is a sudden change of active runway occurring during the descent (which I often saw happen in real life), requiring me to select a different STAR and approach (Lets say I am some 30 nm out at about 10,0000 ft when that occurs, already setup with a STAR and approach, but must change it). At that point, I am way past TOD. I can select any other approach I want, but cannot select the STAR connecting to that approach (= Invalid entry). I am stocked with the STAR I selected before TOD. I know I should not compare the 777 to the NGX, but just for the sake of the discussion, I can do it in the NGX, so I figure there must be a way with the 777 also. I just haven't found it yet.

It does not matter if I select the new approach or the new STAR first. The result is the same (Invalid entry).

7 hours ago, downscc said:

I flew into KIAH the other day when TS Cindy was passing by, was set up for the DOOBI arrival landing ILS26L where entry into the arrival was at AEX.  On descent but before AEX the flow switched at Houston Bush, and since this location uses different STARs for East vs West arrivals, I had to switch to GESNER and ILS08L.  I don't recall having to do anything other than close the discos and over write some of the left over DOOBI.  I don't recall precisely but I probably entered FLCH while the vertical path was being recomputed and maybe added a little thrust in HOLD to adjust.... I don't always recall the details.  This pretty much supports Andy's comments.  Had I been past AEX, I still should have been able to negotiate the changes but with a little more splicing maybe and more or less thrust to modulate the descent profile.

Dan, I tried that route to KIAH and encountered the same problem as anywhere else. I flew from New Orleans (KMSY FL300 J58 AEX DOOBI arrival for ILS 26L at KIAH). I was able to change the STAR and approach at will, back and forth many times (having to rearrange the route of course to remove the DISCO) until reaching TOD (which was past AEX). At TOD, I was setup on the DOOBI for ILS26L but once past the TOD, no way it would accept the GESNER for ILS08L (or any other STAR), but it accepted the ILS08L approach which I activated.

So I ended up with the DOOBI arrival (for runway 26L), and the ILS 08L selected. I opted to reselect ILS 26L and land on 26L.

Flying on HDG and FLCH while I try to make the change (vs remaining on LNAV/VNAV) did not change the result.

If you have the chance to try it as I did, I would be curious to know if you succeed or not (don't risk scrapping an important flight for this though). If you succeed, then I'll know for sure that the problem is ME.

Best regards to both of you.

[spesimen 135]

5 hours ago, NBouc said:

 

If you have the chance to try it as I did, I would be curious to know if you succeed or not (don't risk scrapping an important flight for this though).

no problem, i enjoy testing out random flights and stuff. 

seems like it worked fine for me! not sure what you are doing differently.

here's a short video. starts just before TOD...already loaded DOOBI.26L ...waited a bit till i was descending nicely, then i was able to switch to GESNER.8L ... i also switched back and forth again to see if anything weird happened but it seemed mostly like everything working as expected?

hopefully that provides some useful clue !

cheers,-andy crosby

 

[downscc 1,327]

14 hours ago, NBouc said:

no way it would accept the GESNER

I read back over your past posts in this thread and I believe you are seeing INVALID ENTRY when you try to select a different STAR such as GESNER that is coded for an approach other than you have selected. I think but your explanation of your attempt at KIAH wasn't precise enough.  You said you had DOOBI and ILS26L selected, then said it wouldn't accept GESNER (due to INVALID ENTRY message?) for ILS08L; but, did you still have ILS26L selected?  You should first select ILS08L then select the STAR.

If you look at a SIDSTAR file, such as kiah.txt, you will find that many STARS have runways specified.  When you select a star that doesn't match a specified runway you will get an INVALID ENTRY.  I'm not positive, but I think the FMS still allows the selection of the STAR if it doesn't match if you just ignore the message.  Regardless, to change arrival first change approach then arrival.

Interesting side note is that DOOBI includes all runways, which is the same as not listing any runways.  Just a quirk in how Navigraph translates the navdata from ARINC to this old macro language syntax. Here is GESNER:

STAR GESNR1.08L FIX ZEEKK AT OR BELOW 20000 AT OR ABOVE 17000 SPEED 280 FIX GESNR AT OR BELOW 16000
AT OR ABOVE 13000 SPEED 280 FIX KENNN AT OR BELOW 11000 AT OR ABOVE 10000 SPEED 250 FIX KNGWD AT OR
BELOW 10000 AT OR ABOVE 8000 SPEED 240 FIX ZOEEE 7000 SPEED 240 FIX OVERFLY CASST 6000 SPEED 210
TRK 267 VECTORS
 TRANSITION AEX FIX AEX FIX EMGEE AT OR ABOVE 24000 FIX SCHEX AT OR BELOW 27000 AT OR ABOVE 22000 SPEED 280
 TRANSITION CARPR FIX CARPR FIX MURFF AT OR BELOW 27000 AT OR ABOVE 22000 SPEED 280
 TRANSITION PLANB FIX PLANB FIX CARPR FIX MURFF AT OR BELOW 27000 AT OR ABOVE 22000 SPEED 280
 TRANSITION SWB FIX SWB FIX DLAKE AT OR ABOVE 24000 FIX DOOTL AT OR BELOW 27000 AT OR ABOVE 22000 SPEED 280
  RNW 08L

Hope this helps.

[NBouc 54]

13 hours ago, spesimen said:

here's a short video. starts just before TOD...already loaded DOOBI.26L ...waited a bit till i was descending nicely, then i was able to switch to GESNER.8L ... i also switched back and forth again to see if anything weird happened but it seemed mostly like everything working as expected?

hopefully that provides some useful clue !

Thank you very much Andy for that video. I really appreciate the effort. The way you do it is how I have always done it, but it still does not work for me with the 777.

I flew the route again (KMSY to KIAH) with your video on my second computer just to compare and replicate your actions at the same moment and order. We are doing the same thing in the same order but with different results. I was setup the same as you with DOOBI and ILS08L active before passing AEX, I initiated the change of approach and STAR at the same location you did (10nm from JERNY while in descent) making sure that my indications on the PFD, MFD and MCP were the same (they were except VNAV put my AT in SPD mode instead of HOLD like yours - but that should not be a factor).

In the DEP/ARR page, I was able to select ILS08L but as soon as I clicked the LSK for GESNR1.08L, I got an "Invalid entry" message on the FMC. The FMC did not update with that STAR since it cannot be selected as a result of the invalid entry. I tried again with a different Livery, just in case (PMDG House instead of my usual Air Canada one) and got the exact same problem.

At least, your video shows me that it should work. I am running Prepar3Dv4 with the latest Hot Fixes for both P3D and the 777, but the problem was already present before those updates. To add to the puzzle, I have the same problem with the 777 in Prepar3Dv3 (but not with the NGX). I initially used AIRAC cycle 1509 and recently installed 1707 and encountered the problem with each one, so I can probably discard the AIRAC content as a possible cause.

My conclusion is that there must be something in my setup that is creating the problem. I am tempted to uninstall and re-install the 777, but having read Kyle often say to others that it is not the best way to try and correct a problem because it may sometimes introduce new problems makes me hesitate.

So I am back to the drawing board, but have no clue as to what causes the problem.

 

4 hours ago, downscc said:

... You said you had DOOBI and ILS26L selected, then said it wouldn't accept GESNER (due to INVALID ENTRY message?) for ILS08L; but, did you still have ILS26L selected?  You should first select ILS08L then select the STAR.

Hi Dan, I initially had DOOBI and ILS26L selected. When I tried to change for GESNER and ILS08L, I selected ILS08L first (which was added to the LEGS page)  then tried to select GESNER but got an (Invalid entry). Being unable to select GESNER, I end up with DOOBI.26L and ILS08L in the FMC, with a DISCO in between (the DISCO is normal and expected at that point).

Since I cannot change the STAR, the most logical step is to re-select ILS26L and carry on with the DOOBI arrival and ILS26L.

 

At this point, I don't know what else I can try to solve the problem. I want to thank you all for the time spent at trying to help me, I really appreciate it. In my 32 years of FlightSims, including many years with PMDG aircrafts, this is the first time I just "don't know what's going on".

I will come back to this tread if I find the solution.

 

Best regards and appreciations.

 

[downscc 1,327]

59 minutes ago, NBouc said:

Since I cannot change the STAR, the most logical step is to re-select ILS26L and carry on with the DOOBI arrival and ILS26L.

Yeah, but it's unpleasant to accept something that's not right.  Hmmm... you select ILS08L then try to select GESNER.08L and you get an invalid entry message???  Hmmmm. What if you select VFR Runway 08L then GESNER.08L?  Same result?  I assume your navdata is reasonably current.  What if you change destinations.... then change back to KIAH and set up GESNER.08L to ILS08L?