I'm having problems how the JS4100 FMC interprets a SID. The SID in question is the KENET2M from runway 26L at London Gatwick. I'm using Airac version 1107 Rev 1 in both the JS41 and the 737NG (FS2004), i.e. from the same source. The 737NG displays the SID exactly how it should be flown according the UK NATS AIS chart, but when the same SID is loaded into the JS41 its completely different and unflyable. For some strange reason instead of flying track 259 degs from the runway, it turns immediately left on track 149 degs for 48.6 miles to a waypoint called TK259 ?? It then flies to MID VOR, then D064H, then back to MID VOR then Direct KENET, totally missing out a couple of MID DME based waypoints. I was going to bring this up with Navigraph on their forum, but as the 737NG flies it perfectly, I assume the problem lies within the JS4100 FMC as they both use the AIRAC from the same source. The KENET2M text file is as follows : SID KENE2M RNW 26L TRK 259 UNTIL 10.0 FROM FIX MID FIX D064H AT OR ABOVE 3000 FIX MID 4000 TRK 259 UNTIL 10.0 FROM FIX MID TURN RIGHT DIRECT FIX KENET Any JS4100 FMC experts out there Glen

I have not tried that specific SID with the J41, but I do know that the FMC is not able to fly many (complex) SIDs due to its rather simplistic design/implementation (the J41 FMC is more akin to a fairly basic GPS unit). I have raised this with PMDG and the response indicated that the FMC was in fact limited and standard practice was to fly SIDs by hand using conventional mavaigation, eg VOR/DME etc. Once you are aware that the autopilot may not fly the SID well automatically, it is fairly straightforward to work around and fly as per the chart by hand or with the autopilot.Gerard

Hi Gerard Perhaps I was expecting too much from the FMC, maybe this will get some work for the SP2 upgrade due out after NGX.

I have raised this with PMDG and the response indicated that the FMC was in fact limited and standard practice was to fly SIDs by hand using conventional mavaigation, eg VOR/DME etc

I've just tried the SID manually, it was actually quite good fun. I think I'll take your advice and leave the SID/STAR's out of the FMC. Glen

Hi Glen, I think that you;re referring to a "glich" when, I don't know the right phraseology so forgive me, there's some reference to track rwy heading. J41 is unable to execute that, so in order to have your SID working you need to remove "track" (first) waypoint from it, and fly that part manually. That's how I do this, not very elegant solution, but fast and effective. I bet this would be fixed already if not that delay with NGX... Regards,

Hi Grzegorz Yes the first part of the SID 'RNW 26L TRK 259 UNTIL10.0 FROM FIX MID'. I assume this will be used also with the 737NGX (when I can get it, site current closed due cyber attack) so I may leave it and just fly SID's manually. I am also getting the SID flying away from MID to D064H then back to MID again - don't know what thats all about.... it definately needs looking at. Thanks for your help and information, much appreciated Glen

That flying away and then back is related to that glitch. By deleting I didn't mean to delete them permanently from SID file (I too own other PMDG aircraft) but after loading SID into FMS just remove that first waypoint from procedure, this way the only part you will need to fly manually will be tracking rwy heading, then engage autopilot which will fly the rest of SID. Regards,

Yup, this is definately a JS41 FMC problem. I have just loaded the KENET2M SID into the new 737NGX and it displays on the Nav screen exactly how it should do. Hope this is fixed in SP2 otherwise I won't be using SID's and STAR's in the JS4100 FMC anymore. Glen

Hm, as you wish, but I'm using them without bigger problems, and STAR's are not affected at all.

I looked into this, looks like MID and TRK259 are included twice for some reason. Will fix for SP2 (assuming there is an SP2). Regards.Ernie.