ISSUE DESCRIPTION
With .33 and .31 the 787 VNAV not longer directly pops over to (captures) the GS on an ILS properly. The red diamond that indicates the GS is white even after capture, but will turn red as it should if you disengage the GS and reengage after directly entering the ILS in the flight plan Sighhhh.
FREQUENCY OF ISSUE
Three flights in a row into SFO. This is at SFO. Not sure if others see this elsewhere.
REPRODUCTION STEPS
Please list clear steps you took in order to help our test team reproduce the same issue:
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File an IFR flight plan with flight planner that ends on an ILS
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Fly the flight making sure all step downs are correct in VNAV
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See if you can go directly to the ILS when the VNAV leads in under the glideslope… should sit on the localizer until GS is captured and diamond turns red.
YOUR SETTINGS
What peripherals are you using, if relevant:
Not relevant
MEDIA
Please add a screenshot or video of the issue occurring.
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Just replying to myself here since I very carefully flew this problem approach this AM.
I am a California local and I fly from RENO Nevada to SFO most morning since this is a nice sightseeing flight and am interested in weather. i have an IFR flight plan that has work perfectly for 6 months. The plan feeds into a STAR called ARCHI that leads to the ILS 28 R approach at SFO.
I took notes this am:
When you arrive over ARCHI at 7000’ you can pick up the localizer.
When you go under 6000’ you can pick up the GS.
When you intercept both you are at 4000’ and under the GS. The little triangle is white.
You capture the GS (Goes off in the flight director) but it does NOT turn RED.
You seem to head down the GS but the speed controls are not available… so you are going down the GS at 220 knots.
If you unclick the GS and reclick it you go back on GS with the RED triangle.
Now this may seem like splitting hairs but if you actually fly IFR these are the sort of thing that land you into trouble… devil is in the details.
It should just pick up the GS and take you down to the runway…
I’ve had the same problem on both the 737 Max and 787. When the ils instrument gliderslope crosses the middle it won’t disengage VNAV. Turning the autopilot / app mode on and off at the precise time engages the G/S but it’s tricky. KLAX and EGLL default airports.
Yes, you can still kluge it together by disengaging the AP, do a direct ENTRY (Green Button) and then activate the GS.
I have not tried an ILS into LAX. Does the problem exist there? Guess so. It used to work fine into Fresno (KFAT). Used a complex STAR at the end of a very scenic flight down the High Sierra from RENO.
There must have been 20 BUGS they fixed on this aircraft for SU4 but I suspect they screwed this up when they fixed something else. The devs can probably backtrack.
I focus on the 787 because it is one generation more advanced in terms of AP than the older Boeings. It would be great if they could get this to work perfectly… they are almost there.
PS Used to do professional work in flight simulators and am instrument rated.
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Same problem at KFAT (Fresno California). I had to hack my way through the kluge and of course the airspeed was too fast leading to a hot landing. This is not the way to teach people IFR procedures with an AP/GS that does not work right.
I went over this in detail again today and the 787 AP is seriously broken in SU4.
I flew two flights.
To prove the point started at NUQ 21 miles from SFO and entered the ILS. Then used the main autopilot disengage. AP enunciator showed off but tracking diamond stayed on the flight director… but did not track ILS. It will not even fully disengage so I can restart the ILS. Tried several things and cannot get back to the ILS once disengaged.
Hope others can try it to reconfirm.
I think I have found “the” bug in the AP as there is a very nice video on the ILS transition by I believe a 787 Captain that shows and automatic transition from VNAV to the GS:
This now seems to be gone in SUD4. Have to check if only at SFO or elsewhere.
This also exists at Travis AFB near SFO. This video says should not happen also:
I had a similar issue yesterday when approaching via ILS. The VNAV didn’t disengage automatically when the GS was auctually being followed. What I did was just pressing the VNAV button so mannually disengage the VNAV and it worked…
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Thanks so much for reporting this so that I do not appear to be on the lunatic fringe!
Yes, that is the work around… disengage the VNAV, but that is not the normal procedures from what I can see in either the manuals or the videos.
It just makes sense that the AP should flip over to the most precise guidance without human intervention.
Where was your ILS? I mostly fly in California where I flew when I was a lot younger. Some of the MS Flight Planning software airports seem to be missing their ILSs. I have a few on the East Coast where I flew when much much younger and should check those out.
I’m not seeing the issue, but to test, can you post a flight plan and I’ll duplicate the flight to see if it happens?
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Sure, I just flew flights from Philadelphia into Newark and JFK and on neither was there a smooth switch from VNAV to the ILS. On JFK had to go back and forth between VNAV.GS/turn GS off/then GS again. JFK and Newark respectively:
Here is a nice flight plan my standard route from Reno Nevada to SFO over the mountains. I fly at 16,000’ … the others at 10,000 to start and then drop down to 2000 to intercept the ILS. At SFO the drop is to 4000’.
I spent a little quality vacation time checking out the exact transition from VNAV to the GS on the ILS and here it is in three screen shots.
- 4200’ VNAV coming onto GS/LOC white bar in GS indicatory and diamond in white outline and G/S in annunciator in white.
- 3900’ annunciator G/S vanishes white bars still there and white triangle centered correctly for G/S descent
- Turn off VNA button and annunciator shows G/S in green magenta diamond now captured correctly.
- I think this should happen automatically without disengaging the VNAV…
Did you arm APR (Approach) before reaching the Glide Slope?
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Yes, if you see the annunciator shows the GS in white and when it gets to the point of capture it turns green but the magenta diamond does not come on and the white bars stay there covering the GS error dots.
You could just go down the GS on VNAV but there is no speed control as VNAV sets speed so you go down the GS at 230 knots. This make for an interesting landing.
You have to turn off the VNAV and then the GS pops up. It did not do this before SU4 became live. It was OK on all the Betas. I think they did a lot of work on the aircraft but did not test the work in the Betas just dropped it in at the end with unforeseen consequences.
Have a lot of time on my hands for the Holidays and ran the same type of approach into JFK and Newark…
Hi there,
tested today with a short flight… VNAV PATH works fine but missed swapping to GS MODE on the final approach.
I made a short testing flight from LIRF to LIRP.
Hope this helps.
Merry Christmas to everyone.
Cheers…
Gioc
One more piece of information. This is a comprehensive 787 guide from MSFS 2020:
This pretty much says it all as to what no longer works:
