I keep getting the same problem flying the SRN7G/ABE9Q DP out of LIMC (under FMC control). I have loaded the latest Navigraph AIRAC 1107.Everything is OK until I overfly OLPUR. Then the SID calls for "turn left to ADARI" (see below from the SIDSTARS folder). ADARI is at about 8 o'clock at that point, so the turn should not be ambiguous at all.Yet, the FMC very briefly commands a right turn, then immediately centers and LNAV disconnects. I made sure I am above the 12,500 alt constraint in case that might have been the issue. I also made sure the bank limit is 30 deg since it is a fairly tight turn. Does anyone have an explanation for this?Thanks.PhilSID SRN7G RNW 35R TRK 348 UNTIL 1168 TRK 358 UNTIL 4.1 FROM FIX MMP HDG 080 INTERCEPT RADIAL 125 TO FIX SRN FIX SRN AT OR ABOVE 6000 TRANSITION ABE9Q FIX OVERFLY OLPUR AT OR ABOVE 12500 TURN LEFT DIRECT FIX ADARI AT OR ABOVE 14000 FIX NIKMO FIX ABESI

I keep getting the same problem flying the SRN7G/ABE9Q DP out of LIMC (under FMC control). I have loaded the latest Navigraph AIRAC 1107.Everything is OK until I overfly OLPUR. Then the SID calls for "turn left to ADARI" (see below from the SIDSTARS folder). ADARI is at about 8 o'clock at that point, so the turn should not be ambiguous at all.Yet, the FMC very briefly commands a right turn, then immediately centers and LNAV disconnects. I made sure I am above the 12,500 alt constraint in case that might have been the issue. I also made sure the bank limit is 30 deg since it is a fairly tight turn. Does anyone have an explanation for this?Thanks.PhilSID SRN7G RNW 35R TRK 348 UNTIL 1168 TRK 358 UNTIL 4.1 FROM FIX MMP HDG 080 INTERCEPT RADIAL 125 TO FIX SRN FIX SRN AT OR ABOVE 6000 TRANSITION ABE9Q FIX OVERFLY OLPUR AT OR ABOVE 12500 TURN LEFT DIRECT FIX ADARI AT OR ABOVE 14000 FIX NIKMO FIX ABESI

The FMC logic doesn't think it can make the turn directly so it thinks briefly about turning the other way in a near 270 degree attempt and then gives it up... I assume you're going at a good clip; try it slower and see what happens.DJ

The FMC logic doesn't think it can make the turn directly so it thinks briefly about turning the other way in a near 270 degree attempt and then gives it up... I assume you're going at a good clip; try it slower and see what happens.DJ

Thanks for your reply. I have tried again at 200 kts, with no success. LNAV tries a bit longer before disconnecting but all attempts are to the RIGHT. I tried to help by forcing a left turn towards hdg 000 before switching back to LNAV but again, it keeps trying to turn RIGHT then recenters several times. Never ever attempts a LEFT turn. This is wierd.I'd be curious to see how the "other" 737NG handles this SID but this is clearly the wrong forum... In the meantime, I'll look for other SIDs with similar patterns and try them out.Phil

Thanks for your reply. I have tried again at 200 kts, with no success. LNAV tries a bit longer before disconnecting but all attempts are to the RIGHT. I tried to help by forcing a left turn towards hdg 000 before switching back to LNAV but again, it keeps trying to turn RIGHT then recenters several times. Never ever attempts a LEFT turn. This is wierd.I'd be curious to see how the "other" 737NG handles this SID but this is clearly the wrong forum... In the meantime, I'll look for other SIDs with similar patterns and try them out.Phil

If I get a chance over the next couple of days I'll try it with both planes and let you know the results...DJ

Thanks for your reply. I have tried again at 200 kts, with no success. LNAV tries a bit longer before disconnecting but all attempts are to the RIGHT. I tried to help by forcing a left turn towards hdg 000 before switching back to LNAV but again, it keeps trying to turn RIGHT then recenters several times. Never ever attempts a LEFT turn. This is wierd.I'd be curious to see how the "other" 737NG handles this SID but this is clearly the wrong forum... In the meantime, I'll look for other SIDs with similar patterns and try them out.Phil

OK, I just flew this in the PMDG -700 and it tracked the turns perfectly... I hit OLPUR at 250 kt at FL150 and the turn was just fine... if you like I'll try it in the 'other' 737 as well.DJ

OK, I just flew this in the PMDG -700 and it tracked the turns perfectly... I hit OLPUR at 250 kt at FL150 and the turn was just fine... if you like I'll try it in the 'other' 737 as well.DJ

DJ,Thanks for trying this for me. This is very odd because I have tried it several times with the same result. One possible explanation is that I have the original -700, not the one that was updated along with the -800/-900; which version do you fly?I'll try again and attempt a recording. I will also make sure there is no wind; I don't see how it wd make a difference but who knows?Cheers,Phil

DJ,Thanks for trying this for me. This is very odd because I have tried it several times with the same result. One possible explanation is that I have the original -700, not the one that was updated along with the -800/-900; which version do you fly?I'll try again and attempt a recording. I will also make sure there is no wind; I don't see how it wd make a difference but who knows?Cheers,Phil

I have the updated version that came along with the -8/-9 combo which would be 1.3 I believe. The computed turn arc is fairly broad and the a/c turns better than computed at 25 deg bank limit...DJ