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Guest krullenbol

Atc instruction: Keep present heading

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Guest rellehenk

Hi thereSometimes ATC asks me to fly the current heading when passing a certain waypoint. I am flying LNAV at that moment and just before passing the waypoint I switch to heading mode. I entered the same heading as displayed on the ND (but this track, not heading, right?)But when there is a strong crosswind the heading is not the same as the TRK displayed on the ND. Because when I enter the TRK in my heading display on the MCP, the aircraft can fly another direction up to a few degrees. How can I calculate the heading that I have to fly after a certain waypoint? Do some airlines display the heading on the ND and others TRK?I hope somebody has an answer for meBest Regards,Floris Hartog

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Guest Nexus82

ATC are supposed to correct for wind when they vector you, so just dial in the heading which they tell you and do NOT make wind corrections.And I believe the TRK or HDG of the leg is depending of the navdatabase ( in real life), and not something you can control?I hope it clears some things out.

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Don't really understand what you are looking for here. If ATC is telling you to fly a heading then your on radar vectors. Why do you need to calculate the heading after a "certain" waypoint? Now, if radar vector's end and ATC clears you to fly using your own navigation then just slecet the waypoint on line 1L of the FMC, line select 1L again, push EXEC, engage LNAV, and now you have a course direct to your waypoint. To fly "present heading", just align the Heading Bug with the Heading Pointer ( the tri-angle on the outside of the compose rose) to fly the current heading. Yes, airlines have the option to use HDG or TRK on ND's. I think you'll mostly see TRK used though.Floyd

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Guest ba747heavy

This is one area where I think the real NG autopilot is lacking, a 'heading hold' function, like the 763 has. In any case, usually I just turn the AP heading knob until it reads what my NG says in the heading box. The difference between track and heading isn't that much in my experience, and (using my experience on VATSIM as a controller) we won't notice the difference anyway :)Edit, I don't know the answer to your question, and yes my method is pretty rough ;)

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Guest rellehenk

What I meant: When you are flying inbound a certain waypoint you can read the current track on your ND. Sometimes atc says "After 'waypoint' fly current heading". But when I dial the TRK (displayed on the ND) in the HDG windows on the MCP, and then select heading mode, it is possible that the aircraft is flying towards another direction (just a few degrees depending on the wind) because there is a crosswind that was corrected using LNAV, because When flying LNAV the crosswind is being corrected automatically. With heading select this is not the case. Thanks for all other answers

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Guest Zapper

Gents,IRL. We always keep the HDG bug centred regardless of lateral mode. So when you turn at a waypoint you will also follow around with the HDG Bug. This way when ATC say 'Cancel STAR, steer HDG 170' or somesuch it is just a matter of selecting HDG mode and then steering the aircraft with it until told to resume pilto nav to a particular place/waypoint etc.Rgds,

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Guest Hawkeyeted

If I understand your questions correctly, you want to know how to MANUALLY CORRECT for wind drift when in HDG HOLD mode? Such as: You're in LNAV with a TRACK of 270, but there is a crosswind from the South (Left), so your HEADING is, say 267.You want to use the HDG HOLD function to manually accomplish the same thing? This is where you need to look at the ND, prior to engaging HDG HLD. Your TRACK is ALWAYS displayed as a straight up-and-down white line to the 12 O'Clock position. But, look at the ND for a little white diamond either left or right of the TRACK line. That is the HEADING that LNAV is using to TRACK the desired course (Track and Course are the same thing). In the example, LNAV would hold the HDG of the aircraft at 267 to TRACK 270.You want to dial into the HDG the bearing that corresponds to the white diamond. Now, if ATC orders a heading change, all bets are off. You'll need to OBSERVE the ND for drift, and compensate accordingly.....Of course, you could always get an E-6B computer if you're really THAT concerned about wind drift.

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Guest rellehenk

Thanks, this is the answer where I was looking for :-jumpy

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Guest rcarlson123

But again, as Niklas says, you aren't supposed to correct for wind when told to fly a heading by ATC. If ATC asks for heading 040 for example, dial 040 into the MCP, engage HDG mode, and let the wind push you where it will. It's up to ATC to compensate for winds in the area. (I'm speaking as a VATSIM controller, not a real-world one ... perhaps it's different in the real world.)For example, at Boston where I control, if I know we have a stiff wind from the southeast, and I want a pilot to fly a downwind for runway 22, I might tell him to fly heading 050, which is 10 degrees right of the actual downwind course. (Bad example, I know ... we probably wouldn't be using runway 22. :))

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Guest SimonRigby

Hi folks,Not trying to be argumentitive but several people keep repeating "if ATC asks you to fly a certain heading". I thought the original question was if ATC ask you to "maintain current heading". Just a thought.Simon Rigby

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Guest Zapper

Hi Guys, Just to clarify. IRL, all over teh world. When you are told to maintain HDG, or to turn to a new one that is what you do. You point the aeroplane in THAT direction and do not correct for wind. This means that in the Boeing you select HDG mode on teh AFDS and turn the HDG Bug to where you are told.ATB,

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Guest zip

The rule of thumb is that you fly the assigned heading, altitude and speed. If you ack the instructions, it is understood that you can fullfill the instruction. If you cannot do it, say "unable" and state the reason why. ATC will do all it can to solve your problem.

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