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[Guest OscarP]

Hi!Let me start by thanking for a great product, I purchased the PMDG B737NG a few weeks ago and now it's the only aircraft I fly, everday on VATSIM. I fly in FS2004 and frame rates are good, even though I've heared that this product should be FPS consuming.Well, during an approach a few days ago the ATC told me to turn right to heading 060, I disconnected LNAV, entered 060 and engaged HDG mode. The aircraft started turining, and leveled off, I didn't tink more about that at the time...After a while the ATC asked me to confim my heading was 060 as his radar indicated I was one a 067 heading, I checked the MCU and confirmed that 060 was the heading, but when I checked the ND I noticed that that the aircraft actually was tracking 067, just as the ATC saw on his scope.I don't know if the 7 degree error was because of crosswinds or something else but shouldn't the AP automatically compensate for winds and stuff so that the aircraft is actually tracking the heading entered in MCU? Is this some kind of magnetic variation error?Besides this my 737NG works perfectly up to date. Thanks for reading!Oscar Pilgrim, SAS614

[ahaka 0]

I've noticed that instead of maintaining a magnetic heading, the 737NG tracks it! I wonder if pilots can override the track mode some way, since heading given by ATC are normally not meant to be wind-compenstated.

[Mats_J 2]

Hi Oscar,If ATC tells you to keep 060 HDG it is assumed that you are dialing in 060 in the HDG. Depending on winds you will possibly get a different TRK. This is something you should not compensate. If ATC want's you to keep a certain track they will tell you so. i.e. SASxxx turn right to TRACK 060. But it's quite unusual.Besides that. The discrepancy between your HDG and TRK was probably caused by cross winds. And no A/P keeps the HDG you have dialed in. No compensating in HDG SEL. Of course this is different in LNAV where the FMC has a track to follow.Hope it helps,

[marcom 139]

"shouldn't the AP automatically compensate for winds and stuff"Hi Oscar,well, I don't know what you mean by "stuff" but the autopilot will not correct for crosswinds in HDG SEL as it's exactly that: heading select. If you have a 50 kt crosswind your track will vary greatly (depending on TAS). If ATC then wonders about your track, well that's just the controller's error. The AP will correct for heavy gusts that "turn" the aircraft away from a heading, but that's it. Some aircraft (A320, 777) have autopilot modes to maintain a specific track, but ATC will not ask for this (except to maintain a track from or to a specific VOR/NDB as non RNAV equipped aircraft are not able to comply)Regards,Mark

[Guest OscarP]

Okey, thanks Antti, Mats and Mark for your replies. I've learned something new and know what to tell the ATC next time!

[Guest tmetzinger]

>Okey, thanks Antti, Mats and Mark for your replies. I've>learned something new and know what to tell the ATC next>time!Just tell the controller "heading 060 confirmed sir, would you like to assign a new heading?" as a subtle reminder that wind correction is HIS problem when he's giving you vectors.