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MistyBlue

Can someone explain track up versus heading up?

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I'm trying to wrap my head around track up versus heading up. Been reading about the different modes, but I'm still confused.Often, I'll select a heading using heading select in track up mode and the aircraft does not follow the heading I specify, but rather an offset. For example, I might select 180 on the Hdg bug, but the aircraft will fly what appears to be a heading of 173. Now, am I correct in assuming that in order for the aircraft to fly the selected heading of 180 given the current wind conditions, it must actually fly 173 to maintain the input heading (e.g. crabbing)? I recall in the real world when I flew light planes, I had to adjust for drift given wind conditions, so I had to crab the plane to achieve the true heading I was looking for. Perhaps with Track Up, this is automatically done for you?I just want to make sure that when ATC says "fly heading 180" that when I select 180 the aircraft flies 180, not 173. Don't want ATC yelling at me for not following directions!TIA


Tony

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Heading is where the aircraft´s nose is pointing. Track is what is actually flown. So if you have 180 dialed, you fly heading 180, but due to wind the airplane flies track 173. The ATC gives you heading, not track, so that matters in case of radar vectors.

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Hi TonyYou are correct about crabbing etc. If you are flying with a direct tail or head wind there will be no crabbing. With strong side wind the crabbing effect can be extreme at times. When ATC gives you a heading to fly you follow that heading either flying manually or using the automatics. If you used to fly light aircraft you would have been shown how to work out headings & tracks using a circular slide rule. In the UK we used to use C.D.M.V.T (Cadbury Diary Milk Very Tasty) C=Course D=Deviation M=Magnetic V=Variation T=True. All these calculations are worked out for airline pilots by the FMC & the Nav dispalys heading, wind dircetion & speed plus the track the aircraft will fly for the conditions at the time. Weather you chose to have track or heading up in the NGX is a personal choice. If you take a look at Angle of Attacks website Nick shows this setting & his preference in one of the earlier videos prior to the NGX release.

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Unless ATC specifically states otherwise, all headings issued are headings and not tracks. If you're on VATSIM, some of the rookie radar controllers may say something about it (just like the 250 knot speed limit under 10,000) when they don't account for the wind, but don't pay any attention. I got chastised for my speed once where the radar controller actually stated "I hope you know you're breaking a Federal Aviation Regulation," to which I replied, "I hope you know you're ignoring the wind aloft. Indicated is 240." (ATC only sees your groundspeed, but some of them don't fully understand the difference between groundspeed and indicated airspeed, or which the FAR actually specifies).Again, ATC will compensate for wind and adjust your assigned heading appropriately. The only time I've really heard ATC give tracks instead of headings is over in Europe. Mike would have to confirm that, though. I haven't done much flying on that side of the ocean.


Kyle Rodgers

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Yeah - some of those kids on VATSIM crack me up with that stuff... 1 knot over 250 and they're calling the virtual FAA examiner, hilarious. I've seen it with crossing restrictions too, you're like 100 feet off and they're screaming haha. It's fairly rare to see that with a center controller though, they don't let you man that position until you know what you're doing.A lot of them don't understand that heavies get exemptions to the speed rule too - you can see it on our 744 at high GW - the clean speed is actually higher than 250 and an exemption is always granted in the real world so they don't have to fly with flaps out up to 10,000.


Ryan Maziarz
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Yeah - some of those kids on VATSIM crack me up with that stuff... 1 knot over 250 and they're calling the virtual FAA examiner, hilarious. I've seen it with crossing restrictions too, you're like 100 feet off and they're screaming haha. It's fairly rare to see that with a center controller though, they don't let you man that position until you know what you're doing.
Yeah, once you get a guy to center, he's normally smart enough about the regs to know what's going on. A lot of the time, the rookie radar guys don't know that the restrictions aren't so much regulatory (you could probably make the argument that they are), as much as SOP based so that you're not screwing the next guy over with an aircraft that's too high. That's pretty much the only reason they're there.On the other side, I think some of the pilots think ATC hawkeyes their speed, and if they're 1 knot over, it's the end of the world and they're getting a phone number and their cert pulled. Yes, it's a reg, and if an examiner was sitting right behind you, he might take issue seeing the indicated speed above 250, but ATC isn't going to notice if your GS is about the same as everyone else's.
A lot of them don't understand that heavies get exemptions to the speed rule too - you can see it on our 744 at high GW - the clean speed is actually higher than 250 and an exemption is always granted in the real world so they don't have to fly with flaps out up to 10,000.
Too few people know about the exemptions to that rule, specifically for the one you mentioned. I love the MY FMC IS MAKING ME BREAK A REG!!1!! comments in the 744 forum.FAR 91.117(d)I guess most don't get much farther than (a)...

Kyle Rodgers

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Ok, thanks guys. I do realize heading is the direction the nose is pointed versus track is the heading the aircraft is truly tracking over the ground based on wind correction. But I'm still a bit confused as to what ATC is actually looking for when they assign a heading. Based on what Jan said above, ATC says fly 180, I dial 180, and hit HDG SEL and I'm good. But if I dial 180 and the aircraft is tracking 173 based on wind correction, then I'm not really flying 180 right? I could see ATC coming back saying I'm not complying with the assigned heading. So then do I adjust the bug to, say, 187 so that the aircraft tracks 180? Or am I totally off the mark here?It's been a long time, but if I recall, in the real world I just flew the heading assigned, regardless of wind. So I'm guessing what Jan said is how you fly it.


Tony

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Ok, thanks guys. I do realize heading is the direction the nose is pointed versus track is the heading the aircraft is truly tracking over the ground based on wind correction. But I'm still a bit confused as to what ATC is actually looking for when they assign a heading. Based on what Jan said above, ATC says fly 180, I dial 180, and hit HDG SEL and I'm good.But if I dial 180 and the aircraft is tracking 173 based on wind correction, then I'm not really flying 180 right? I could see ATC coming back saying I'm not complying with the assigned heading. So then do I adjust the bug to, say, 187 so that the aircraft tracks 180? Or am I totally off the mark here?It's been a long time, but if I recall, in the real world I just flew the heading assigned, regardless of wind. So I'm guessing what Jan said is how you fly it.
If ATC says "Fly heading 180," you dial 180 in the MCP. That's it. No tricks.If ATC doesn't like where you are tracking, he'll give you another heading.

Matt Cee

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If you select 180 you will be fine in my experience. Even in the real world, I was bringing a 172 into Jax one day almost sideways...lol...a bit exaggerating bit you get my drift. If they are paying attention, they will understand what is going on, but you are flying that heading,, just not cleanly.

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But if I dial 180 and the aircraft is tracking 173 based on wind correction, then I'm not really flying 180 right? I could see ATC coming back saying I'm not complying with the assigned heading. So then do I adjust the bug to, say, 187 so that the aircraft tracks 180? Or am I totally off the mark here?
Totally off the mark:
Again, ATC will compensate for wind and adjust your assigned heading appropriately.
If ATC says "turn right/left heading" or "fly heading" they want you to fly that heading with no compensation on your end (put the nose of your airplane on that exact number). Again, a controller should be applying the appropriate wind correction on their side. Don't overcomplicate it on your end. When you're getting to the point they start assigning vectors, you should be paying attention to other things.

Kyle Rodgers

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Ok, thanks guys. I do realize heading is the direction the nose is pointed versus track is the heading the aircraft is truly tracking over the ground based on wind correction. But I'm still a bit confused as to what ATC is actually looking for when they assign a heading. Based on what Jan said above, ATC says fly 180, I dial 180, and hit HDG SEL and I'm good.
Yep, he or she gives you a heading, knowing that the track might be different. (RL Atco here)

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Hey guys, in the Airbus A320 is so easy to switch between Heading and Track just by clicking a button, but in the 737 I can't see how to tell the aircraft to follow a track instead a heading (and switch to FPA mode instead Feets/MIN). I know maybe it's a stupid question.. :S

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Hey guys, in the Airbus A320 is so easy to switch between Heading and Track just by clicking a button, but in the 737 I can't see how to tell the aircraft to follow a track instead a heading (and switch to FPA mode instead Feets/MIN). I know maybe it's a stupid question.. :S
Different way of doing things - no button needed. On the NGX, whether you are fitted with Heading up or Track up options (selectable from the FMC options settings) both pieces of information are always displayed. See FMC 10.11.36 and 10.11.43 for the details about the two types of display.

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