Hello Captains:I have been having a devil of a time performing the loop 6 departure out of LAX. A bit of background first. I have had no issues with the departure using the PMDG 747X. I am finding out that the 737 is quite a different animal in the way the autopilot works--due to my lack of training on the 737. (I am so immersed with the 747 procedures that I find myself having to undo what I learned). I have completed tutorials one and two without trouble, but those SIDs are not complicated and there is no "vectoring" involved.For example, in the 747, I perform a manual takeoff. When I reach 400 feet, I click on HDG SEL and HOLD, which keeps the aircraft flying on the runway heading. (But, there is no HOLD function on the 737--unless I missed it). At 1,000 feet, I select VNAV and then "C" CMD. Now, if ATC assigns vectors, I simply dial the heading and press HDG SEL, and the aircraft will follow the new heading. When ATC then clears me direct to LAX, on the legs page of the FMC, I click on LAX to place it in the scratchpad, then I click over "Vectors." I press EXEC and then on the MCP, I press LNAV and the aircraft now goes directly to LAX. I have tried to do the same procedures on the 737 without luck.On the 737NGX, this is what happens....I perform a manual takeoff without LNAV, VNAV, and HDG SEL armed. After passing the INTC (this is where the SMO radial 160 intersects the runway heading of 250 degrees, you are supposed to be below 3,000 feet. After I pass this intersection, the FMC deletes the "VECTORS" and "LAX" entries, and you end up with the waypoints of KEGGS, COOP, and DAG. (This never happened in the PMDG 747X.) I have tried all different combinations of LNAV, VNAV, etc., and cannot prevent VECTORS and LAX from disappearing. Obviously, I am doing something wrong, but I don't know what concept I have missed. So....Does anyone know the real-world way to perform this departure with the 737NGX? (By the way, I do remember someone posting a video on YouTube years ago with the PMDG 737 that was made for FS 2004, but I can't find it.)Any input would be much appreciated. If possible, I would love to see a tutorial on the proper way to perform a SID that uses vectoring and then, eventually, connects to a way-point.Thanks in advance.Robert Amster

You may have meant this when you say you tried all combinations, but did you take off with LNAV armed? VNAV on or off should have no effect.

It's strange that it would delete the VECTORS as well as LAX entry. I will have to try this one later, but the way it SHOULD work is to depart just as you described, then at some point while on the 235 or 250 heading ATC will give you a somewhat southerly heading for a few miles followed by direct LAX (or sometimes DAG if there's no traffic but I think that's mostly a VATSIM thing). Normally at that point I would select LAX on my FMC and engage LNAV, but if it had deleted it then you just have to do one more step to add it back at the beginning of your FP. From what you're describing, it doesn't sound like you're doing anything wrong. I'm interested in trying this out now, I don't think I've flown the LOOP in the NGX yet.

As for HDG HOLD function, this is not installed on the 737. You should have runway heading input before takeoff by standart procedure anyway, so using HDG SEL mode should suffice.

Thanks Fabo, Noah, and Spin737 for your comments!Fabo--yes, the heading of 250 degrees is already set in the heading as part of standard procedures before takeoff.Spin737 -- what I meant was that I tried LNAV armed before takeoff, then VNAV before takeoff, then HDG SEL before takeoff, then LNAV and VNAV armed before takeoff (these were four separate takeoffs) with the same problem of the disappearing way-points.Noah -- please let me know how your takeoff went with the LOOP SIX departure. Yes, I have added LAX back to the legs page but when you are the only one flying the aircraft keeping track of heading, speed, etc., it is a chore to get that entered in quickly. I'm sure real pilots would complain if after takeoff their way-points were missing too!!!! This is either a bug or I am not performing the procedures correctly. Regards,Robert Amster

Robert - Just did it and the exact same thing happened to me. I was looking at the heading bug when it happened but I 'think' as soon as I crossed the SMO 160 radial is when LAX disappeared from the FP - but I can't be certain. I took off with HDG SEL and VNAV armed. I flew manually to about 1500 feet then engaged the AP. All appeared to be fine and as I approached the SMO 160 radial I looked to the MCP to change the heading and when I looked back at the ND, LAX was gone.I have done the LAXX departure several times and dont ever recall this problem before.

Maybe a stupid question butafter disappearing, does the PROG page show LAX at LSK 1L?

after disappearing, does the PROG page show LAX at LSK 1L?

I didnt look at the PROG page, however it did disappear from the LEGS page.

Just tried this - I see the same thing... I'll talk to Vangelis about it.The procedure could be improperly coded in the navdata - it's using an INTERCEPT command on the SMO R-160, which is sorta weird because you never actually fly that radial. When it gets to that (INTC) point, there's turn prediction, so it's actually right over top of LAX and it somehow sequences that waypoint too.In real life I'd be willing to bet this just gets flown in HDG SEL though in real life - you can draw the SMO R-160 with the FIX page and then just go to 235 after passing it.

IRL, on the SID, ATC will more often than not vector you South of the LAX VOR and then clear you direct to a following fix or all the way to DAG bypassing LAX entirely. The LAX fix on the sid plays it's purpose mostly durring lost Comms and having to fly the filed or expected.

IRL, on the SID, ATC will more often than not vector you South of the LAX VOR and then clear you direct to a following fix or all the way to DAG bypassing LAX entirely. The LAX fix on the sid plays it's purpose mostly durring lost Comms and having to fly the filed or expected.

Exactly.

I've flown this departure many times in the real plane using both heading select and LNAV. I prefer LNAV but I'll do what ever the Captain prefers obviously. I will also typically use the FIX page to draw the SMO radial just for reference. In real life the big issue is making sure you make the climb restrictions at LAX KEGGS and COOPP. Everyone has a different technique it seems but I have never had a problem making it by just selecting full climb power and following the normal climb and acceleration profile. I have never been cleared direct DAG on the LOOP6 though. ATC will usually give you the turn back to LAX about the time you pass 4000 feet. Becaue of noise complains by the communities south of LAX they want you to come back to the LAX VOR. I can't recall ever being cleared to any of the fixes further down the line on this departure. I believe they need you to fly to LAX, KEGGS and COOPP so you have defined points for the altitude crosings because you are headed toward the highest point of the highest mountains north of Los Angeles. The crossing resrictions assure will have adequate terrain clearance.

I have flown this back in 2002 in a brasilia over and over again when it wasn't the loop6 I forget what revision. But we were always vectored south of lax for the turn to the north as long as Victor 299 and or 165 was ocupied with traffic.But why argue?Just outa curiosity, you know why the altitude restriction exists off the 25's centerline under 3000 on the sid?

Maybe they have different procedures for turboprops. I flew the Brasilia for three years at Continental Express out of Cleveland. I enjoyed flying it.I believe the restriction is because there is a VFR shoreline class B transition route out there. At least that's what I've been told is why there is that restriction.

Maybe they have different procedures for turboprops.

Yeah maybe they do.

I flew the Brasilia for three years at Continental Express out of Cleveland. I enjoyed flying it.

I enjoyed it as well. It was definately very engaging, not to mention dirty and noisy. :)I had an old freind who used to fly for Contenental Express around that time or maybe a bit earlier. He was flying outa Texas and an FO in the early ERJ's if I remember correctly. Roger Gross is his name. Ever ran into him?

I believe the restriction is because there is a VFR shoreline class B transition route out there. At least that's what I've been told is why there is that restriction.

Yeah, the Special VFR flight rules corridor. Transitioning altitude is or was 3500 Southbound and 4500 Northbound. Gotta love flying in SoCal.