LNAV commands 360 deg ex-LLBG Rwy 30. Why ?!

[JSACKS 0]

Departing LLBG rwy 30 on straight-ahead basis for first 22 nm, LNAV commands a 360 deg turn left or right prior to close wp 298b or any other nearby wp when it engages moments after liftoff. It then flies the route normally after completing the 360 around the entire airport and departure rwy area. I cannot understand what is going on here. The 360 deg command is active during hand fly or AP departure. I've checked the DEP page, rwy, LNAV, V-speeds, I cannot imagine what I am missing.Why would LNAV command a 360 thus ?Jonathan

[rgamurot 1]

Is the waypoint straight in front of the rwy or do you have to turn to intecept it? The only thing I can think of that would cause the aircraft to do this is that you are too close for the aircraft to successfully intercept the wp. You could try to fly the aircraft manually on route for a short period and ensuring the next wp is brought up. Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg

[JSACKS 0]

It is straight ahead of me, 3 nm ahead. Everything is in line directly in front of me for the first 20-22 nm, so this is hugely perplexing.I had trouble at the same airport rwy about 1 year ago and thought I solved it by inserting a wp closer to the departure rwy but now this too seems to have become "corrupted" in some way for this specific departure routing. It is strange. For now I have fixed the situation by changing this first wp to a neighboring wp that is close by and I also have changed wp no. 2 to an NDB and so far (fingers crossed!) things are working normally with LNAV after takeoff.I never know whether things like this are "user error" or just glitches with no rational explanation in the sim.JS

[JSACKS 0]

Incidentally, almost every departure is a hand fly for me to flaps-up with the 744 because it's fun and challenging. But this particular departure with the programmed waypoints that are giving me a headache go nuts with both hand fly and with AP departure.Jonathan

[rgamurot 1]

If you're still having problems if you are hand flying the aircraft, I'm afraid I am at a loss for answers. I hope there is someone else out there with some idea of what's going on.Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg

[crvm 0]

I have seen this at KSFO too. It is best to HDG SEL until passing this first wpt or to LSK the next active wpt after flaps up then engage LNAV. I believe there is something going on with the SID in these cases.. Best,Randy J. Smith<<>>

[JSACKS 0]

Yeah, OK, Randy, I am sure you're quite correct. Thanks for the suggestion which I shall try. (I just feel sure it's not me in this case!)Thanks.JS