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Guest ilh

SID doesn't really work as it should

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The attached fictional KSFO PORTE3 off the 01s (fictional because I increased the turn from SFO 4 DME to 8 DME to spread things out a bit) exhibits a problem with the logic following the SID.The problem surfaces when it is supposed to turn to HDG 200. Instead, it overshoots the turn by at least 20 degrees to 180 or beyond in its attempt to fly back to the magenta line. The thing is, the precomputed magenta line isn't the thing to fly. When it is told to fly HDG 200, it should fly HDG 200. I was testing without wind, but with wind it should not be trying to fly some ground track, but instead the specified heading.Can someone try this out? PMDG, will this be addressed in a future patch? I brought this up previously, and I believe it was acknowledged, but I fear it is falling through the cracks.Will you be adding the ability to specify left/right turns in a SID for those cases where you need to make a turn greater than 180 degrees?Lee Hetherington (KBED)

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Lee:That's one of my favorite departures (along with the KSAN Border4). I'll give it a try in the morning (just finished KMCO-TJSJ in 767PIC).BTW: I noted that you are flying a heading of 350, the actual SID specifies an intercept of the SFO R-350 ...-michael

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Thanks. I know about the R-350 but forgot to mention it. I had that in at one point and decided to simplify it for the bug report. With the 4 DME and the R-350 the map gets really cluttered with close waypoints. Besides, the heading 350 right after 1000' puts you pretty close to R-350 at 4 DME.Yeah, I love that departure. It is one of the more interesting in the US with all of the radio navaids. Let's see, DME plus two VOR radials even before PORTE.BTW, I was flying this with zero wind.Lee Hetherington (KBED)

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Lee:I gave it a try and got basically the same results as you.After reaching 1000' AGL, a left turn to 350 was initiated with the aircraft to the right of the magenta line. At 8 nm a left turn was initiated and continued until ~175 degrees. During the turn the aircraft crossed the magenta line and then began very slight course corrections to the right to get back on it.Also note that the magenta line should have been drawn to depict a 200 degree heading to intercept PYE R-135. The magenta line had an actual heading of 215 degrees. I then tried the SID again, this time with a HDG 320 INTERCEPT RADIAL 350 FROM SFO, then FIX SFO8 (defined as Colocated SFO 350 8) as a substitute for the HDG 350 in the first trial.Interestingly, on the ground the FMC showed the HDG 320 INTERCEPT ... as a RIGHT TURN 053 with distance of 6900+ miles! On the ND, there was a solid magenta line that indicated a right turn.However, once airborne, the ND updated with the INTC point clearly shown where it should be (320 heading crossing the SFO R-350). The aircraft flew that portion of the SID flawlessly - nicely turning left to 320 and then right to fly the SFO R-350 radial.But, once I hit the SFO8 FIX the same problem occurred in flying the HDG 200 INTERCEPT PYE R-135 command: an overshoot followed by very slight course corrections. And again, the magenta line was drawn at a heading of ~215 rather than 200.-michaelPS: Another issue was I engaged VNAV on the climbout both times and got the UNABLE CRZ ALT (FMC alt was FL310, MCP alt was 14000, no altitude constraints on FMC waypoints), and a VNAV DISCONNECT).

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