Fix to Fix
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Direct to B will create a track between your present position and B.
If you want to make sure to be on the track joining A to B you need to create a flight plan with A and B and activate the A to B leg.
If you want to make sure to be on the track joining A to B you need to create a flight plan with A and B and activate the A to B leg.
Option A: BPF's method. GPS direct.
Option B (no GPS): custardpsc's method, with my thumb on the map, that has my track with 10 minute marks. DI? Not in my aircraft!
Option B (no GPS): custardpsc's method, with my thumb on the map, that has my track with 10 minute marks. DI? Not in my aircraft!
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There is no official way to fly fix to fix IFR without some form of RNAV/GPS, unless both fixes happened to be on an airway which can be flown using an NDB QDM/QDR, VOR radial or something.
Obviously you can do some form of DR until you happen to intercept a VOR radial or DME arch which also cuts through the fix, and then follow that. But that will not be what ATC is expecting.
And that brings me to the most important point. Obviously you are going to plan/file your route so that you can fly it with the equipment you have on board. No GPS/RNAV capability? Then don't plan to do fix-to-fix ("DCT"). But as soon as you start the flight, especially in busy airspace, the plan goes out the window and you should expect deviations from ATC. Vectors are fine, but if you get a "direct X" without the ability to navigate that with reasonable accuracy, you should simply refuse. In theory, ATC should be able to glean from your equipment list that you don't have RNAV capability so they should not give you those instructions, but in practice, they assume everybody has RNAV capability of some sort and can do a "direct X".
SDF? Had to look it up. It looks to be some sort of navaid that's only used for approaches. Not for en-route navigation. And there's only one location in the world that still uses it. https://en.wikipedia.org/wiki/Simpli...ional_facility
Obviously you can do some form of DR until you happen to intercept a VOR radial or DME arch which also cuts through the fix, and then follow that. But that will not be what ATC is expecting.
And that brings me to the most important point. Obviously you are going to plan/file your route so that you can fly it with the equipment you have on board. No GPS/RNAV capability? Then don't plan to do fix-to-fix ("DCT"). But as soon as you start the flight, especially in busy airspace, the plan goes out the window and you should expect deviations from ATC. Vectors are fine, but if you get a "direct X" without the ability to navigate that with reasonable accuracy, you should simply refuse. In theory, ATC should be able to glean from your equipment list that you don't have RNAV capability so they should not give you those instructions, but in practice, they assume everybody has RNAV capability of some sort and can do a "direct X".
SDF? Had to look it up. It looks to be some sort of navaid that's only used for approaches. Not for en-route navigation. And there's only one location in the world that still uses it. https://en.wikipedia.org/wiki/Simpli...ional_facility
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There is no official way to fly fix to fix IFR without some form of RNAV/GPS, unless both fixes happened to be on an airway which can be flown using an NDB QDM/QDR, VOR radial or something.
Obviously you can do some form of DR until you happen to intercept a VOR radial or DME arch which also cuts through the fix, and then follow that. But that will not be what ATC is expecting.
And that brings me to the most important point. Obviously you are going to plan/file your route so that you can fly it with the equipment you have on board. No GPS/RNAV capability? Then don't plan to do fix-to-fix ("DCT"). But as soon as you start the flight, especially in busy airspace, the plan goes out the window and you should expect deviations from ATC. Vectors are fine, but if you get a "direct X" without the ability to navigate that with reasonable accuracy, you should simply refuse. In theory, ATC should be able to glean from your equipment list that you don't have RNAV capability so they should not give you those instructions, but in practice, they assume everybody has RNAV capability of some sort and can do a "direct X".
SDF? Had to look it up. It looks to be some sort of navaid that's only used for approaches. Not for en-route navigation. And there's only one location in the world that still uses it. https://en.wikipedia.org/wiki/Simpli...ional_facility
Obviously you can do some form of DR until you happen to intercept a VOR radial or DME arch which also cuts through the fix, and then follow that. But that will not be what ATC is expecting.
And that brings me to the most important point. Obviously you are going to plan/file your route so that you can fly it with the equipment you have on board. No GPS/RNAV capability? Then don't plan to do fix-to-fix ("DCT"). But as soon as you start the flight, especially in busy airspace, the plan goes out the window and you should expect deviations from ATC. Vectors are fine, but if you get a "direct X" without the ability to navigate that with reasonable accuracy, you should simply refuse. In theory, ATC should be able to glean from your equipment list that you don't have RNAV capability so they should not give you those instructions, but in practice, they assume everybody has RNAV capability of some sort and can do a "direct X".
SDF? Had to look it up. It looks to be some sort of navaid that's only used for approaches. Not for en-route navigation. And there's only one location in the world that still uses it. https://en.wikipedia.org/wiki/Simpli...ional_facility
I meant SDF for :
S : Standard Equipment composed of VHF RTF, VOR and ILS
D : DME
F : ADF
Yep, I could ask for vectors but my FIs won't... I had to use the CRP5 to do a sort of DR but as it has been stolen I am trying to find another method.
It's mainly to go from a check point to another check point using the same VOR but not the same radial...
Thank for the help
Do you have an HSI or similar?
If so a million years ago during basic’ish military IF teaching we used to teach a technique for point to point/fix to fix using it - I’ll have a go at explaining the method but you’ll need to be gentle with me here....
It works by visualising the HSI as a virtual” MAP” with the VOR at the centre, your position along the tail of the VOR needle and your “go to fix” positioned somewhere along it’s relevant radial out from the centre of the HSI.
Now the slightly tricky bit - The distances you visualise out from the centre of the HSI to “plot” a picture depend on your range and the fix range from the VOR...e.g. if you are at 60 miles and the fix is at 30 then you “draw” yourself at the tail of the needle (at the circumference of the dial) and the fix half way out towards the circumference along it’s radial.
If OTOH you were at 30 DME and the fix at 60 DME then “draw” it the other way around - you picture yourself half way out from the centre, with the fix along it’s radial at the circumference...the idea is to keep both fixes “on” the HSI, the bigger DME needs to be the one you are imagining as on the circumference.....still with me?
Finally, almost... mentally “draw” a line between the two points....mentally drag that line back to the centre of the HSI and bingo, where that imagined line crosses the compass rose is the track to fly to your “go to fix”..
Try drawing it out using simple numbers for starters to get the hang of it...for instance the fix is on the 060 radial at 40 DME and you are on the 120 at 40DME..etc...
Now as some one will recognise from the above I was never an A1 QFI so I hesitate to go any further in trying to explain it without the use of a whiteboard and four colours....not sure if anyone else recognises the technique, if it is still taught or better still if there’s anything online like a handy video that covers it...
It sounds horrid until you get the hang of it but it actually works very well and was actually a very very useful technique for some niche (military) applications in “free” airspace. In the modern real world of controlled airspace trying to comply with ATC I’d commend all the earlier advice about vectors, etc.
If so a million years ago during basic’ish military IF teaching we used to teach a technique for point to point/fix to fix using it - I’ll have a go at explaining the method but you’ll need to be gentle with me here....
It works by visualising the HSI as a virtual” MAP” with the VOR at the centre, your position along the tail of the VOR needle and your “go to fix” positioned somewhere along it’s relevant radial out from the centre of the HSI.
Now the slightly tricky bit - The distances you visualise out from the centre of the HSI to “plot” a picture depend on your range and the fix range from the VOR...e.g. if you are at 60 miles and the fix is at 30 then you “draw” yourself at the tail of the needle (at the circumference of the dial) and the fix half way out towards the circumference along it’s radial.
If OTOH you were at 30 DME and the fix at 60 DME then “draw” it the other way around - you picture yourself half way out from the centre, with the fix along it’s radial at the circumference...the idea is to keep both fixes “on” the HSI, the bigger DME needs to be the one you are imagining as on the circumference.....still with me?
Finally, almost... mentally “draw” a line between the two points....mentally drag that line back to the centre of the HSI and bingo, where that imagined line crosses the compass rose is the track to fly to your “go to fix”..
Try drawing it out using simple numbers for starters to get the hang of it...for instance the fix is on the 060 radial at 40 DME and you are on the 120 at 40DME..etc...
Now as some one will recognise from the above I was never an A1 QFI so I hesitate to go any further in trying to explain it without the use of a whiteboard and four colours....not sure if anyone else recognises the technique, if it is still taught or better still if there’s anything online like a handy video that covers it...
It sounds horrid until you get the hang of it but it actually works very well and was actually a very very useful technique for some niche (military) applications in “free” airspace. In the modern real world of controlled airspace trying to comply with ATC I’d commend all the earlier advice about vectors, etc.
Last edited by wiggy; 20th Aug 2018 at 13:37.
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We do have a lovely CDI in our aircraft.
Thanks a lot for explaining the method Wiggy; I'll be practicing it today and let's see tomorrow during my flight if my FI will not kill me
Thanks a lot for explaining the method Wiggy; I'll be practicing it today and let's see tomorrow during my flight if my FI will not kill me
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I think your FI is not doing this to prepare you for real life. This is just an exercise to see if you can think on your feet, and can visualise what's going on.
What kind of fix did you have to fly to? If it's a pure RNAV fix (just a point in space, identified as lat/long) then it's never going to work. You don't have the equipment to identify the fix even if you're right on top of it, let alone navigate to it. However, if the fix is overhead a VOR, or radial/distance from a VOR/DME, or overhead an NDB, or something like that, then if you manage to come up with a reasonable DR heading/distance, and can eventually find the fix with limited maneuvering in the end, you will probably get the thumbs up.
One suggestion though: In a case like this I try to aim not directly at the fix, but at a point something like 5 degrees left or right of the fix. With DR you know you are going to have to correct your track once you get close to the fix, and if you aim slightly away from the fix, then at least you know in which direction you should be correcting.
So building on the example by wiggy: You are on the 120 radial at 40 DME, and need to get to the 060 radial, 40 DME (draw it out), means you need to fly due North for 40 miles. Now use a DR track of, say 350 or 355 initially. Assuming you did not screw up your wind correction completely, this means you now intercept the 060 radial at maybe 35 DME. Turn right, follow the 060 radial outbound until 40 DME. Or use an initial track of 005 or 010 and intercept the 40 DME arc somewhere near the 070 radial, then follow the 40 DME arc until on the 060 radial. Whatever the best strategy is, depends on what technique you're most comfortable with, but also on what's going to happen after the fix: Which direction are you going to turn then?
What kind of fix did you have to fly to? If it's a pure RNAV fix (just a point in space, identified as lat/long) then it's never going to work. You don't have the equipment to identify the fix even if you're right on top of it, let alone navigate to it. However, if the fix is overhead a VOR, or radial/distance from a VOR/DME, or overhead an NDB, or something like that, then if you manage to come up with a reasonable DR heading/distance, and can eventually find the fix with limited maneuvering in the end, you will probably get the thumbs up.
One suggestion though: In a case like this I try to aim not directly at the fix, but at a point something like 5 degrees left or right of the fix. With DR you know you are going to have to correct your track once you get close to the fix, and if you aim slightly away from the fix, then at least you know in which direction you should be correcting.
So building on the example by wiggy: You are on the 120 radial at 40 DME, and need to get to the 060 radial, 40 DME (draw it out), means you need to fly due North for 40 miles. Now use a DR track of, say 350 or 355 initially. Assuming you did not screw up your wind correction completely, this means you now intercept the 060 radial at maybe 35 DME. Turn right, follow the 060 radial outbound until 40 DME. Or use an initial track of 005 or 010 and intercept the 40 DME arc somewhere near the 070 radial, then follow the 40 DME arc until on the 060 radial. Whatever the best strategy is, depends on what technique you're most comfortable with, but also on what's going to happen after the fix: Which direction are you going to turn then?
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I think your FI is not doing this to prepare you for real life. This is just an exercise to see if you can think on your feet, and can visualise what's going on.
What kind of fix did you have to fly to? If it's a pure RNAV fix (just a point in space, identified as lat/long) then it's never going to work. You don't have the equipment to identify the fix even if you're right on top of it, let alone navigate to it. However, if the fix is overhead a VOR, or radial/distance from a VOR/DME, or overhead an NDB, or something like that, then if you manage to come up with a reasonable DR heading/distance, and can eventually find the fix with limited maneuvering in the end, you will probably get the thumbs up.
One suggestion though: In a case like this I try to aim not directly at the fix, but at a point something like 5 degrees left or right of the fix. With DR you know you are going to have to correct your track once you get close to the fix, and if you aim slightly away from the fix, then at least you know in which direction you should be correcting.
So building on the example by wiggy: You are on the 120 radial at 40 DME, and need to get to the 060 radial, 40 DME (draw it out), means you need to fly due North for 40 miles. Now use a DR track of, say 350 or 355 initially. Assuming you did not screw up your wind correction completely, this means you now intercept the 060 radial at maybe 35 DME. Turn right, follow the 060 radial outbound until 40 DME. Or use an initial track of 005 or 010 and intercept the 40 DME arc somewhere near the 070 radial, then follow the 40 DME arc until on the 060 radial. Whatever the best strategy is, depends on what technique you're most comfortable with, but also on what's going to happen after the fix: Which direction are you going to turn then?
What kind of fix did you have to fly to? If it's a pure RNAV fix (just a point in space, identified as lat/long) then it's never going to work. You don't have the equipment to identify the fix even if you're right on top of it, let alone navigate to it. However, if the fix is overhead a VOR, or radial/distance from a VOR/DME, or overhead an NDB, or something like that, then if you manage to come up with a reasonable DR heading/distance, and can eventually find the fix with limited maneuvering in the end, you will probably get the thumbs up.
One suggestion though: In a case like this I try to aim not directly at the fix, but at a point something like 5 degrees left or right of the fix. With DR you know you are going to have to correct your track once you get close to the fix, and if you aim slightly away from the fix, then at least you know in which direction you should be correcting.
So building on the example by wiggy: You are on the 120 radial at 40 DME, and need to get to the 060 radial, 40 DME (draw it out), means you need to fly due North for 40 miles. Now use a DR track of, say 350 or 355 initially. Assuming you did not screw up your wind correction completely, this means you now intercept the 060 radial at maybe 35 DME. Turn right, follow the 060 radial outbound until 40 DME. Or use an initial track of 005 or 010 and intercept the 40 DME arc somewhere near the 070 radial, then follow the 40 DME arc until on the 060 radial. Whatever the best strategy is, depends on what technique you're most comfortable with, but also on what's going to happen after the fix: Which direction are you going to turn then?
Compulsory point or non-Compulosory on Low IFR routes.
Doing a DME ARC is also nice and precise! But time wasting maybe he will say.
Thanks for your contribution BackPacker!!
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Ticking off each radial sounds like overkill to me, but in general the progression of the DME throughout the track is useful to know. In the example of wiggy, if you're tracking direct to the fix you know that the DME should diminish to about 35 at the 090 radial (halfway through the track), and then increase again.
OTOH, I do notice that instructors tend to ask you more questions like this if you're on the wrong track, hoping that you somehow see your error yourself and correct it. If you're obviously doing well and know it, they tend to start yapping about other stuff. So your instructor may just have been helping you correct the mistakes you made earlier.
Just had a look and there are a couple of basic videos on the technique I tried to describe loaded up on YouTube, though for some reason the links get blocked when I try to imbed them directly here...Try Googling “point to point nav using the RMI & VOR”....
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I try not to fly fix to fix any more as especially in the London area there is so much traffic just following the magenta line and not looking out it has become hazardous.
If I have to flyfix to fix I use the track offset function in the GPS to parallel the fix to fix direct track by a mile or so.
If I have to flyfix to fix I use the track offset function in the GPS to parallel the fix to fix direct track by a mile or so.
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The fix-to-fix thing might just be in the Training Manual, so every FI at your school would have to do it at some point. But as it's not something that's going to happen often in real life, they all tend to use nice, round numbers which work out to easy solutions. As long as you visualise things properly.
Ticking off each radial sounds like overkill to me, but in general the progression of the DME throughout the track is useful to know. In the example of wiggy, if you're tracking direct to the fix you know that the DME should diminish to about 35 at the 090 radial (halfway through the track), and then increase again.
OTOH, I do notice that instructors tend to ask you more questions like this if you're on the wrong track, hoping that you somehow see your error yourself and correct it. If you're obviously doing well and know it, they tend to start yapping about other stuff. So your instructor may just have been helping you correct the mistakes you made earlier.
Ticking off each radial sounds like overkill to me, but in general the progression of the DME throughout the track is useful to know. In the example of wiggy, if you're tracking direct to the fix you know that the DME should diminish to about 35 at the 090 radial (halfway through the track), and then increase again.
OTOH, I do notice that instructors tend to ask you more questions like this if you're on the wrong track, hoping that you somehow see your error yourself and correct it. If you're obviously doing well and know it, they tend to start yapping about other stuff. So your instructor may just have been helping you correct the mistakes you made earlier.
I will follow his method!!!
Just had a look and there are a couple of basic videos on the technique I tried to describe loaded up on YouTube, though for some reason the links get blocked when I try to imbed them directly here...Try Googling “point to point nav using the RMI & VOR”....
Very clever
I guess I just have to ask... WHY? What is the point of this exercise? In FAA-land it is unknown, even before GPS became universal (for example, when I learned to fly in 2001). There used to be a magnificent piece of avionics called the KNS80 which could do this kind of thing. I even tried to read the manual (my plane had one before the previous owner installed a GNS430, so it came with the manual). Programing it in the air, in response to something like "direct DOCAL", would be challenging, to say the least.
Do ATC in the UK really give this kind of instruction to VOR/DME equipped (no GPS) aircraft?
Do ATC in the UK really give this kind of instruction to VOR/DME equipped (no GPS) aircraft?
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n5296s
I have been asking myself the same question, the only answer I can come up with is these people are bored, a few weeks back I found myself teaching a young FO how to do a fix using one NDB some place in Greenland. My excuse was the boredom on a long oceanic sector and the need to stay awake, I can only guess at what the auditors will think if my paperwork gets pulled for inspection.
From a navigation point of view it was a pointless exercise as the ten minutes of ADF bearings and drawing on the map proved to be considerably less accurate than the fix that was available on my iPad. Apart from reenforcing the accuracy of modern navigation kit the message it sent the FO was that My natural position in the scheme of things was as Flight Engineer on a Constalation or stratocruser.
As for talk of the KNS80 you are just like me........showing your age, I just need to add that I preferred the KNS81 linked to the KN63 DME as it had more waypoints and that feature avoided too much re-program in in the air.
From a navigation point of view it was a pointless exercise as the ten minutes of ADF bearings and drawing on the map proved to be considerably less accurate than the fix that was available on my iPad. Apart from reenforcing the accuracy of modern navigation kit the message it sent the FO was that My natural position in the scheme of things was as Flight Engineer on a Constalation or stratocruser.
As for talk of the KNS80 you are just like me........showing your age, I just need to add that I preferred the KNS81 linked to the KN63 DME as it had more waypoints and that feature avoided too much re-program in in the air.
No ATC doesn't routinely give this sort of instruction, though of course lots of the "legacy" fixes were and still are defined as a radial/DME. I think the last time I saw the method being used even slightly in anger ( to cross check a questionable ATC instruction) was on the Classic 747 over darkest Africa. So pre-glass screen, pre a GPS fit....as you say these days it doesn't work like that.
Certainly when I taught it (in a non civvie environment) we knew even then most students would never use the technique "in anger" but the logic for teaching it was pretty much as backpacker described earlier:
.
It certainly was a good instructors tool for seeing how full a student's capacity bucket might be getting....now whether that is relevant in a civilian teaching environment in this day and age is another matter, maybe they should just teach how draw and follow a magenta line.
Certainly when I taught it (in a non civvie environment) we knew even then most students would never use the technique "in anger" but the logic for teaching it was pretty much as backpacker described earlier:
I think your FI is not doing this to prepare you for real life. This is just an exercise to see if you can think on your feet, and can visualise what's going on.
It certainly was a good instructors tool for seeing how full a student's capacity bucket might be getting....now whether that is relevant in a civilian teaching environment in this day and age is another matter, maybe they should just teach how draw and follow a magenta line.
