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Thread: Navigation Question

  1. Default Navigation Question

    Hi guys, I'm in the stage of learning at the moment and have a question that is bugging me.

    Say if (for example) you are approaching an airport on a heading of 252 degrees and you are nearing the VOR for the airport.

    The approach chart tells you to turn onto a radial of 48 degrees upon reaching the VOR, to send you back up the side of the runway (I forget the official term) to then turn back toward the runway into the glide slope and localiser.

    How would I correctly turn to that exact radial from different approach headings? say if I was approaching the VOR on a different heading of 018 degrees, how would I calculate hitting the 048 radial in that instance?

    If this is a daft question I apologise, I feel like I am missing an important calculation and a fair bit of knowledge, I have ordered a navigation tutorial book which will be arriving this week.

    Thanks

  2. #2
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    I'm not sure where you're indicating in relation to the runway, since you give no clue about where the VOR is in relation to the airport, nor do you mention which airport or runway. An actual approach chart (or at least an airport name and the approach name and desired runway) would help a lot in that respect.

    But as for turning on to another radial, if you are inbound on a 252º heading (I'm assuming no wind, since that affects headings) going TO the VOR, that puts you on the radial that is the reciprocal of that, or the 072º radial. Since you want to turn on to the 048º radial, that means you'll need to make a very sharp* right turn and end up on a heading of 048º.

    So as you get near the VOR (how near is speed dependent), you'll need to turn the OBS to 048º and turn right to an initial heading of 048º. As soon as the needle stabilizes you'll want to center the VOR needle with the TO/FROM flag on FROM. That will put you outbound on the 048º radial.

    If you were instead inbound on a 018º heading then you'd be on the reciprocal radial which is the 198º radial, which leaves you a right turn, so rotate the OBS to 048º and, nearing the VOR, start a right turn to 048º, then as soon as the needle stabilizes you'll want to center the VOR needle with the TO/FROM flag on FROM. That will put you outbound on the 048º radial.

    But you might take a look at Rudy_B's tutorial series in the Outer Marker where he has videos on flying the VOR and NDB. You also might consider taking the navigation and perhaps instrument flight lessons that are built in to FS to learn more about this. You could also go to the FAA's Pilot's Handbook Of Aeronautical Knowledge Chapter 16 where they discuss all manner of navigation.
    [hr][/hr]* I can't imagine a turn that sharp in an approach setting, though, since you'd wander off the desired paths by quite a bit. When turns like that are needed on an approach, there are specifically designed procedures for it.
    Last edited by lnuss; 04-28-2020 at 09:56 AM.

    Larry N.

    As Skylab would say:
    Remember: Aviation is NOT an exact Science!

  3. Default

    Quote Originally Posted by lnuss View Post
    I'm not sure where you're indicating in relation to the runway, since you give no clue about where the VOR is in relation to the airport, nor do you mention which airport or runway. An actual approach chart (or at least an airport name and the approach name and desired runway) would help a lot in that respect.

    But as for turning on to another radial, if you are inbound on a 252º heading (I'm assuming no wind, since that affects headings) going TO the VOR, that puts you on the radial that is the reciprocal of that, or the 072º radial. Since you want to turn on to the 048º radial, that means you'll need to make a very sharp* right turn and end up on a heading of 048º.

    So as you get near the VOR (how near is speed dependent), you'll need to turn the OBS to 048º and turn right to an initial heading of 048º. As soon as the needle stabilizes you'll want to center the VOR needle with the TO/FROM flag on FROM. That will put you outbound on the 048º radial.

    If you were instead inbound on a 018º heading then you'd be on the reciprocal radial which is the 198º radial, which leaves you a right turn, so rotate the OBS to 048º and, nearing the VOR, start a right turn to 048º, then as soon as the needle stabilizes you'll want to center the VOR needle with the TO/FROM flag on FROM. That will put you outbound on the 048º radial.

    But you might take a look at Rudy_B's tutorial series in the Outer Marker where he has videos on flying the VOR and NDB. You also might consider taking the navigation and perhaps instrument flight lessons that are built in to FS to learn more about this. You could also go to the FAA's Pilot's Handbook Of Aeronautical Knowledge Chapter 16 where they discuss all manner of navigation.
    [hr][/hr]* I can't imagine a turn that sharp in an approach setting, though, since you'd wander off the desired paths by quite a bit. When turns like that are needed on an approach, there are specifically designed procedures for it.
    Hi thanks for your response, I kind of made it up as an example, maybe I will find an actual chart to use as an example. (Sorry about that) I meant the VOR station to be at the airport.

    I will go over what you said in regards to lining up with the radial, its hard for me to grasp at first glance but I will go over it and try to let it sink in. I am fine with flying vor to vor, but vor to an approach heading confuses me as I am not tuning into anything. Am I correct in thinking that you might fly to that vor from many angles? So you would need to calculate is that correct?

    Thanks for the links, sorry if there are areas I am missing such as waypoints and stars etc, it just seems to me that planes would fy into an airport vor from different angles, and would then calculate how to fly onto the radial.

    I got this confusion from doofers youtube video about navigation, his channel is excellent, but he showed a chart for liverpool I think where the vor station was at the airport and it sends you onto a radial. Which made me wonder how would you know what heading to set if coming in at different angles.

    Thanks for the advice I will take it, as I said vor to vor I am proficient, but other things are confusing me, im 2 weeks in so have a lot to learn.

    Thanks again
    Last edited by Adam Chivers; 04-28-2020 at 11:04 AM.

  4. #4
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    as I said vor to vor I am proficient
    Apparently only as long as you're going TO a VOR, if I understand you correctly. But there's a very good reason why they have a TO/FROM flag on the VOR head. Radials are ALWAYS the outbound direction, which would be with the FROM flag showing, while inbound headings (with the TO flag showing) are always the reciprocal of the radial (that is, 180º from the radial). Flying outbound on a radial is as important as (and, once understood, as easy as) flying TO the station.

    Note that only a very few VORs are on an airport, or to say it another way, very few airports have a VOR on the field. So flying to a VOR, flying FROM a VOR, and intercepting a desired radial (both inbound and outbound) are necessary skills for flying with VORs. The radials are actually fixed paths over the ground (in effect -- let's not get into quibbles), magnetically oriented, and easily followed both ways, once you truly understand that headings, courses, bearings and radials are all different, even if one or two will sometimes coincide with another, and once you understand how to fly and intercept desired radials in both directions.

    Note that wind will make things more awkward, so first work with no-wind conditions, only adding winds once everything is well understood.

    Larry N.

    As Skylab would say:
    Remember: Aviation is NOT an exact Science!

  5. Default

    https://www.aurora.nats.co.uk/htmlAI...ics/106486.pdf

    Ok so heres a link to a real example of what I poorly tried to demonstrate. It shows a VOR and a fixed heading of 059 degrees for the approach. My issues are as follows...

    1.Its 059 degrees from what exactly?

    2. In fsx the flight plan will automatically give you a heading from a VOR to an airport but based on your flight plan heading, the heading/radial here is fixed no matter where you are approaching from

    3. Would you work out how to get onto this heading pre flight?

    4. How would you calculate this heading if you are forced to deviate from the flight plan and back to the VOR on an unplanned heading

    5. Sorry if point 4 was what you already answered, trying to understand it still at present

    Thanks if you can help and apologies for the wishy washy nature of the original post

  6. Default

    Thanks, I really need to learn about reciprocals and what that means, so I will study that, If I can get a grasp of all this I will be very pleased. I replied again with a better example, basically I sit and watch people on youtube manually tuning all the headings in the a320 on approach, and I just wonder how on earth they know what to do. So I figured id learn approach charts but I was instantly stumped by this lol thanks

  7. Default

    Reciprocal means opposite. So the reciprocal heading means the opposite heading.

    ---
    A radial is a fixed heading from a VOR. (or from another beacon or waypoint).

    ---
    In your first post you are heading To a VOR. On a heading of 252 degrees.
    The opposite of your direction of flight is 072.
    (252 - 180degrees = 072)


    you want to fly away from the VOR at 048 degrees. (radial 048 of VOR.). You are flying to the VOR at heading 252.
    So you need to make a right hand turn before getting to the VOR.

    Not a full 180 degree turn. Slightly less.
    That way you end up flying away from the VOR, on a heading of 048. (keeping the VOR behind you.)

  8. Default

    I think I get it now, Ive got a feeling that Ive been incredibly stupid, all headings fixed or not, including a pilots heading are always supposed to be true to fixed NSEW aren't they. Ive been so silly lol

    Thanks so much for your patience, Ive crammed a lot in my head in 2 weeks and some of the basics get blurry
    Last edited by Adam Chivers; 04-28-2020 at 01:36 PM.

  9. #9
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    Quote Originally Posted by Adam Chivers View Post
    https://www.aurora.nats.co.uk/htmlAI...ics/106486.pdf

    Ok so heres a link to a real example of what I poorly tried to demonstrate. It shows a VOR and a fixed heading of 059 degrees for the approach. My issues are as follows...

    1.Its 059 degrees from what exactly?
    First, there is NOT a VOR on that chart. There IS an ILS, which consists of a localizer (horizontal guidance) and a glide slope (vertical guidance), and most other things in the approach are referenced to it, BUT the magnetic COURSE LINES (not headings) are directions over the ground by the compass, regardless of your heading (the way the nose points).

    When you tune your NAV radio to certain frequencies it knows (by design) that they are localizers, and that they are designed for a single purpose, that is, to guide you to the runway. The needle gets 4 times as sensitive and the OBS is useless.

    You are trying to run a marathon before you've gotten fully into the walking stage. Instrument approaches are an advanced skill, and there's a reason that the FAA requires a minimum of 40 hours of instruction, plus a lot of ground instruction/hitting the books, to get an instrument rating. And that's AFTER getting the Private ticket and some experience (and they require 40 hours of instruction plus ground school for THAT, and it includes how to use a VOR). Take it in steps. Your knowledge hasn't reached the Private Pilot stage yet, so learn to fly the VOR first, with all it's variations.

    And you must first learn the difference between heading and course. Learn the difference between true course and magnetic course. Learn the difference between headings, courses and bearings. Learn the difference between an ILS (including the localizer and the glide slope) and a VOR and a VORTAC and an NDB. These are ALL important things for you to know, so that you can form the mental concepts needed and so that you can understand what people are talking about when they use these technical terms.

    You might also want to realize that the 059º on that chart is part of a procedure turn for Category C and D aircraft (064º is for Category A and B aircraft), while the localizer has a fixed course line of 267º (there ARE no radials). That's what localizers do. Period.

    When you are confused about VOR vs ILS, you're in a bit over your head and you need to back up and learn some basics first so that you'll understand the more advanced areas more easily. The FAA's Instrument Flying Handbook can help with some of that, but so can the manuals aimed at the Private Pilot.

    Quote Originally Posted by Adam Chivers View Post
    2. In fsx the flight plan will automatically give you a heading from a VOR to an airport but based on your flight plan heading, the heading/radial here is fixed no matter where you are approaching from
    A flight plan in FSX details a specific route. If you are somewhere else, that flight plan can't be counted on until you get back on the planned route. And the flight plan deals in courses, not headings, since it won't know the actual winds in advance. A heading is where the nose is pointed, and with a strong wind could be 30º, 40º or more different from the course, which is fixed over the ground.

    Note that the FAA's manuals are free online to read and/or download, and can teach you a tremendous amount if you'll take the time and effort to read and understand what they say, along with practicing some of that information in the sim, and you can even ask questions about what you read, but please start with the simpler ones first, such as the Airplane Flying Handbook, the Pilot's Handbook of Aeronautical Knowledge, and the Student Pilot Guide, as well as the Aeronautical Information Manual (AIM).

    And finally, I've spent somewhere near two hours trying to get some explanations across to you, and I normally don't mind doing explanations, but I DO expect that someone asking questions will spend some time and effort learning on their own, using THEIR hours of time, AND going through materials I've pointed them to, before asking me (or others here) to fill in all the details.

    In addition to the FAA manuals I've linked to, Wikipedia has a wealth of information on aviation, and you can get some of your answers there. You can also spend time going through Rudy_B's videos in the Outer Marker, where he covers much of this material, complete with visual aids, and you can learn more effectively that way than by asking some questions here where you apparently are getting more confused.

    Again, I don't mind answering questions, but PLEASE do yourself a favor (as well as me) and use the more effective means of learning first, THEN come back with questions you still have. I'm not trying to chase you off (far from it) but I DO want you to learn effectively and with no more time spent and confusion involved than needed, which those videos will do for you.

    Larry N.

    As Skylab would say:
    Remember: Aviation is NOT an exact Science!

  10. #10
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    A radial is a fixed heading from a VOR.
    Actually, that's a fixed course or compass direction, not heading. Following a radial, the heading might be different by 30º or 40º, depending on winds.

    Larry N.

    As Skylab would say:
    Remember: Aviation is NOT an exact Science!

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