STAR problem

[daan_vb 37]

Hi there,I was flying into Zurich LSZH airport today and tried to fly the Rwy 35 BLM1G STAR, with a GIPOL transition. I programmed this into the 737NG FMC but it was riddled with DISCO's. Is this a problem with the Navdata or is it something i'm missing with the FMC progrmming? Do i have to update these DISCO's manually.I'd appreciate any help you can give,RegardsDaniel

[ronzie 21]

I had this happen preflight but not when the LEGS page was up during flight. Try going to the final legs page where the transition starts. If you do this more than once you will get a disco. There should only be one DISCO that you need to close up.I also found some of the waypoint coordinates in the SID/STAR database incorrect. These are usually soft waypoints labeled like DT110. Check out the SID/STAR files on planepath.com and navdata.at. Dan Downs will probably reply with a better solution.

[daan_vb 37]

Hi thanks for the reply. I will try your idea next time i fly into Zurich. I had another little problem flying out of Zurich using the VEBIT2S SID out of rwy 16. The initial turn is too tight and the FMC gets confused and half through the turn, it turns the plane the other way. Surely thats not normal. Do i have to fly the first part of the SID manually?

[downscc 1,327]

The first problem isn't as interesting as the second one.The last fix of a star should end with a vectors command or it should be the same as the first fix of the approach. Otherwise, you'll get a disconnect and the easy thing to do is manually connect the route on the legs page.If a star is not well written you may get additional disconnects at conditional fixes, such as fly xxx heading until intercepting yyy radial but the heading misses the radial (usually because FS9 mag variation is obsolete in many locations).If an approach is not well written you will also get disconnects in a missed approach procedure. In all of these cases, you can either look for a better procedure or learn to edit it yourself (and share it with others hopefully).The second problem is odd. The PMDG will never give up on a turn and start turning the other way because the turn is too tight. It will overshoot the fix it is turning to and then attempt to get to that fix by whatever means it finds easiest. Unfortunately, it doesn't just sequence the fix it got close to but missed and go onto the next fix. Keep in mind the faster you are flying the larger the radius of your turn becomes. There are DPs I've look at that have 230 KIAS speed limits to keep everyone close to the same track.

[daan_vb 37]

Thanks for the reply Dan. I tried manually deleting the disco's on the FMC and it allowed me to delete some but not others. I will have a look and see if i can edit the STAR maanually.As for the SID, well i had a look at the charts and it says not to exceed 210kts. I tried flying it again at this speed and sure enough, half way through the turn it turned the other way. However it is still looking for the first fix. I don't know why it does this because it looked like it could pass the fix if it kept its bank angle. Strange and quite annoying lol.

[ronzie 21]

On LSZH departures I use yoke and heading control. I sometimes have to advance the waypoints in the LEGS page. If I think it is the departure I recall that first waypoint was really tight and a soft waypoint that I retained 5 degree flaps and 180 kn until that first turn was complete. I continued using HDG until the longer leg out of that turn, increased speed, and cleaned up the flaps. After the first significant turn there was another based on direction of departure which was a fly by where the ND displayed an anticipated turn track which missed overflying that waypoint.On cockpit videos I have of Zurich departures these intitial legs are indeed flown under yoke yaw control with the PF getting guidance from the FD and ND displays. Some of those waypoints are labeled DT110 or similar (soft waypoints) are there to establish limits to the pattern meaning do not fly past them but it is OK to turn before them and not overfly.As to why the aircraft broke off the turn (did the CMD or LNAV disconnect) I can only think it exceeded bank limit or was approaching a wing stall and an auto-recovery took place.I am not at home where I have the plates but these soft waypoints I describe are at Zurich and or EDDK Cologne.

[ronzie 21]

Regarding the turn:I have the plate for VEBIT DP out of Rwy 16 in front of me now. The are no RNAV waypoints for a precise left turn crossing near the KLO VOR to merge with the 055 (To 235) radial of WIL (BREGO VOR). That radial represents the northern limit of your travel. The take-off turn commences using KLO as a DME reference at D1.0 and the rate of turn increases at D2.4 KLO. Coming out of the turn to cross just north of KLO at midfield to BREGO but not flying further north than R055 WIL. This is not a tight turn but you are pretty busy. Notice coming out of the turn you do not have to proceed direct to BREGO but just not go north of the 055 radial. I would leave flaps 5 and use a speed of 180 for the turn. I would command ALT - FLCH and SPD of 180 and manipulate with yoke and transition to HDG until crossing BREGO (WIL) which should be the first waypoint on the LEGS page. On the EICAS panel uise the APT and VOR switch to give you references on the ND to assist in guiding yhour turn. Tune VOR 2 to KLO to get DME and tune VOR 1 to WIL with course set at 235 to show the 055 radial boundary on the ND. Once you are at BREGO increase to 210 and clean flaps. HDG to point to ZH588 and on track you can engage LNAV if your LEG stack popped of BREGO/WIL. If not manually advance the top LEG to ZH588 or if not present VEBIT for a direct to LNAV once you are on the track line for BREGO to VEBIT.It is a very busy departure. I have done this mostly with HDG until past BREGO. Putting KLO on the LEGS to cross over would indeed be too tight a turn.Hope this helps regarding the system breaking out of the turn. Your displayed track unless it is in the FMC database will not be correct until you cross BREGO. Just use the left turn crossing the airport symbol and Kjust north of the KLO VOR symbol and slope toward BREGO not crossing your course guide at 0235 WIL.

[daan_vb 37]

I engaged LNAV just after D1.0 and the aircraft then begins to turn towards D2.4 KLO. It was during this turn that the autopilot breaks the the left hand turn and then starts turning right. The LNAV didn't disconnect. I was travelling at 210 kts with flaps up, so i will try and fly it at 180 with flaps 5 until past D2.4 KLO with some manual control.I have one more question. How do i manually advance the top LEG in the FMC. When i first flew the departure I couldn't remove the D2.4KLO that the FMC wanted to fly and ended up removing the whole SID in the FMC.Your explanations of the SID was very helpful and i very much appreciate the advice.

[downscc 1,327]

Advancing fixes on the legs page is done with the left side buttons (LSB). For example, to promote the second fix to the top, press the second LSB from the top, then press the top LSB. Don't forget EXECUTE.