TACAN Navigation

[Avio]

Hope this is the right place to post this :-

 

When navigating purely by TACAN tracking only, how does one keep to each precise track along a planned route? (with only one HSI and no other VOR/TACAN indicator).

 

A good example is following a specific departure or arrival route, where there are a series of specific heading turns, with each segment crossing a certain TACAN bearing and DME distance.

 

Gets extra challenging when done with cross-winds or in low visibility.

 

On a separate but navigation related issue, after creating a mission with several checkpoints, is there a way to output print a table showing the various flight plan headings and distances of the created route? Like that in MSFS?

 

Any advice much appreciated.

Edited January 7, 2017 by Avio

[PiedDroit]

TACAN gives you a bearing to the station.

Align this bearing with the radial you want to follow and it means you'll be on course.

 

For example, let's say you want to approach a TACAN station from radial 121.

Opposite bearing is 301.

You can either set course selector on HSI (when available...) to 301 and the horizontal deviation indicator will visually tell you if you're off course.

 

Or simply fly by aligning the needle of TACAN with the 301 bearing.

If they're not on top of each other (i.e. TACAN bearing is not 301), it means you're off course.

With wind, it will be the same thing exactly, except your aircraft might be flying on a different heading, to compensate for the wind.

For example, if, in order to maintain the TACAN needle on 301, you need to fly heading 305, it's OK, it only means you have a bit of wind.

 

When you're set on the radial, watch the DME distance indicator to time your turns.

 

If you're off course, fly slighly off until both needles are on top of each others, then turn back on desired heading.

Example, TACAN station is at bearing 280, you want to enter the airspace through radial 121 (which means flying on 301).

You can fly a fixed heading intercept (ex: 30° intercept means you fly 271 until you intercept the radial). But flying a fixed intercept angle when you're really far from course might take you a lot of time to get there.

 

You can adjust intercept angle according to the heading difference.

For example, 301-280 is roughly 20, so add another 20 to your heading to fly 260. Needles will start closing each other. When difference is 10 (i.e. TACAN needle is at 290), fly to heading 280. Until you intercept.

If the DME distance is big, you can even fly a straigher intercept (higher angle) to get there faster.

Edited January 8, 2017 by PiedDroit

[Avio]

Thank you PiedDroit for your wonderful post. I know about Tacan Vor tracking. What i meant is how in real world a pilot could track through various waypoints that each is defined by a bearing and distance from some Vor or Tacan a distance away. One could dial in the correct Tacan and bearing course and head towards the waypoint, but crossing it at exactly the specified bearing and distance from that Tacan is really a hit or miss guess work, further complicated by wind and visibility.

 

Give a simple example here - takeoff and fly heading 30 degree then turn to 350 then 280 then 210 degrees, with all waypoints defined from one single same Tacan. Can that be done precisely in planes with only one Tacan device?

[PiedDroit]

Thank you PiedDroit for your wonderful post. I know about Tacan Vor tracking. What i meant is how in real world a pilot could track through various waypoints that each is defined by a bearing and distance from some Vor or Tacan a distance away. One could dial in the correct Tacan and bearing course and head towards the waypoint, but crossing it at exactly the specified bearing and distance from that Tacan is really a hit or miss guess work, further complicated by wind and visibility.

 

Give a simple example here - takeoff and fly heading 30 degree then turn to 350 then 280 then 210 degrees, with all waypoints defined from one single same Tacan. Can that be done precisely in planes with only one Tacan device?

The next step is what's called "point to point navigation" (google it).

There isn't any magic here, when you reach your radial/distance waypoint and switch to a another waypoint you're on your own.

If you know the heading to the next waypoint, just fly it and you would intercept the radial just as I described it above.

 

If you don't know the heading, you need to figure out what it is, for this you either guesstimate (as in the video), or use a calculator and a little trigonometry voodoo to compute the bearing.

 

When flying this way it's best to avoid long legs, in order to have frequent course correction

If you know the wind speed and direction then you can apply wind correction (using an E6B for example).

 

You can also look for tutorials about how to figure out a bearing/distance of a bandit using bullseye calls, because it is the exact same technique that applies. Just replace the bull's eye with the TACAN station and the bandit with your next waypoint.

 

Edited January 8, 2017 by PiedDroit

[Avio]

Thanks again for all the helpful advice.

 

Totally agree this method good for short legs only. Trying to nail even close to it is hard enough.

[PiedDroit]

Thanks again for all the helpful advice.

 

Totally agree this method good for short legs only. Trying to nail even close to it is hard enough.

Welcome :thumbup:

When flying like this you're not expected to achieve sub-NM accuracy :D

But it is a very good exercise and it will be very helpful with bullseye calls also, so, totally worth it.

[Dangerman]

Point to point navigation using tacan as taught to students on Hawk T1 back in the day. Essentially what has been said above already but using a different method to establish your new heading.

 

1. Look at tacan needle radial and your distance on HSI

2. Imagine the HSI is a top down view of your piece of the world.

3. You are the end of the needle, (your radial)...on heading indicated by HSI.. at distance indicated by DME. Essentially the end of needle is where you are and the needle gives the scale.... so it is for example 20 miles long if you are at 20 DME

 

4. Plot (imagine) on your HSI which radial and range you want to get to. Imagine where the needle would be for that radial and dme. E.g. If it is xxx radial at 10 miles, you know your needle is 20 miles long cos you are at 20dme...so the 10 mile point is half way in to the centre....use the hdg scale to visualise where the needle will be at the new radial... but remember your imaginary needle for the new point is now shorter cos you want to get to 10 miles on a radial compared to the 20 you are at.

 

5. Once you have visualised where you want to get to, turn towards it until your imagined point is directly above your actual point indicated by radial and range ( tail of the needle).

 

6. You are now pointing at the new point defined by the same tacan.

 

Consider this extremely simple example

 

Hdg 360

Tacan/ DME indicates 180 radial at 20 miles

New waypoint is 180 radial at 10 miles

New point visualised and placed "above" actual point (tail of needle) gives hdg as described above. ...... hdg 360 degrees

 

New heading?

 

Now try it with different radials/DME to get to

 

No maths, no trigonometry

 

I would draw a picture but too tricky on an iPad

 

Good luck....

Edited January 14, 2017 by Dangerman

[Avio]

Thanks Dangerman. Going to try figure that out.