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YaYoSky
1st Oct 2010, 18:47
hi all,
i find the definition on some website.
"A track is a line on a chart or across the terrain that an airplane is following or intending to follow. It is a vector, which means it is given as a starting point and a heading.
A course is a line between two points on earth. Usually given by stating the names of the starting and ending points."

Is there some difference between track and course?

Hahn
1st Oct 2010, 18:56
There is a difference according your definition: the course has an end, the track leads to infinity. In practice the difference is pretty much f... all!

renard
1st Oct 2010, 19:04
I would say they are the same thing, like color and colour.

Track would tend to be used in English English.

Course would tend to be used in American English.

Dani
1st Oct 2010, 19:07
In language terms there might be no difference, I don't know.

In aviation there is a big difference.

Track is the real path (vector) the aircraft is flying. Heading plus/minus WCA (wind correction angle) is track.

Course is defined as a line from a VOR. There are courses inbound and outbound (sometimes referred as radial). Where I come from, the word course always implies from/to a VOR (sometimes an NDB, but then it's rather a QDM/QDR).

There might be different definitions in aviation in different regions of the world. I've flown in Europe, Asia, Africa, USA and Australia, and it's always been the same (well, more or less...)

hth,
Dani

aterpster
1st Oct 2010, 19:48
YaYoSky:

Is there some difference between track and course?

Track is the actual flight patch over the ground. If flying a course, and you are maintaining the course, in that case course and track are the same.

That is why most, if not all, RNAV navigators have Desired Track and Actual Track.

Tinstaafl
1st Oct 2010, 21:01
The FAA defines 'course' as "The intended direction of flight in the horizontal plane measured in degrees from North". Practically speaking, regions under American influence use 'course' whilst areas with a British history use 'track'.

Substitute 'inbound course' for 'inbound track', 'planned track' for 'intended course', 'track made good' for 'achieved course' and the like.

eckhard
2nd Oct 2010, 13:39
And just to confuse matters further, the RAF at one time used the word 'course' to mean 'heading'! And in really early publications, they used 'drift' when they meant 'drag'.

I think that these days, 'course' can be thought of as a defined path (usually straight) over the surface, as in a VOR radial or an ILS localiser, whereas 'track' is the path over the surface that the aircraft is actually achieving (as Dani said previously).

Eck

Wizofoz
2nd Oct 2010, 14:19
Course is defined as a line from a VOR. There are courses inbound and outbound (sometimes referred as radial). Where I come from, the word course always implies from/to a VOR (sometimes an NDB, but then it's rather a QDM/QDR).


"From" a VOR has always been refered to as a Radial,not a course, in my experience, and is expressed with an "r" on charts.

I've always also only heard "Bearing" to and from an NDB.

rudderrudderrat
2nd Oct 2010, 15:15
Hi,

In the old days before INS etc. we used to "plot a course" which meant "measure the intended track between two points on a chart". We observed our "track made good" (by Doppler drift angle and heading / or back bearing from the beacon we'd flown (count the dits and dars from Polonis Consul beacon etc.) and did several course corrections (changed heading a bit) until we'd settled on the intended track.

Microburst2002
2nd Oct 2010, 15:47
imagine the route between two navaids. You may wish to follow the course from one of them to the other. Say it is a 034 track.

Another airplane is flying 20 miles to your right with the same track, 034.

both airplanes have a 034 track, but only one is on the 034 course from VOR A to VOR B.

A track is a direction (the direction we are flying to). A course is a direction to or from a point. We can intercept it and follow it.

That is the difference. You can achieve a track anywhere in the world. But you can only follow the 340 course from LIN VOR if you are in Poland.

capt. solipsist
3rd Oct 2010, 12:36
I hope I am not guilty of oversimplification here. The exagerrations though are intentional to make the point.

Imagine you are flying eastward to a distant fix, track 090. If you have crosswind from the left, some wca is necessary to maintain the 090 track. Let's say you need 5 correction, so your hdg now is 085, to maintain track 090.

But a sudden momentary great gust of left crosswind had you offset 2 miles from your previous track. If the wind reverts back to its old values instantly after and no additional corrective input was enabled, you are gonna be back to your hdg of 085 and track of 090.

However, your course to the fix now is no longer 090 as before, but a bit to the left (let's say 088?) due to the lateral gust displacement.

Therefore, hdg 085, track 090 and course 088 now.

:}

cosmo kramer
3rd Oct 2010, 14:54
Track = magnetic heading +/- wind correction angle.
This is describing what is happening at the moment. If you keep this track you are flying a Rhumb line (http://en.wikipedia.org/wiki/Rhumb_line) (assuming no Magnetic variation (http://en.wikipedia.org/wiki/Magnetic_declination)).

Course = Planned line between point A and B without wind correction with reference to true north. May include varying headings if planning to fly a Great circle (http://en.wikipedia.org/wiki/Great_circle). Also needs correction for Magnetic variation

Hence, when flying a course your track will change with magnetic variation and as course changes as a result of Great circle navigation.

mig3
4th Oct 2010, 04:55
Hence, when flying a course your track will change with magnetic variation and as course changes as a result of Great circle navigation.

Which explains why on charts the track between two fixes may be different at either end. Eg. Track from AAA -> BBB might be 340 degrees where as the track from BBB -> AAA might 342 degrees, depending on the distance between the two, lat and long etc. etc.

reynoldsno1
5th Oct 2010, 01:24
... and just to add to the confusion, ARINC 424 navigation database coding specifications are different again:

Track to a fix (TF)
The primary straight route segment for RNAV is a TF route. The TF route is defined by a geodesic path between two waypoints.

Course to a fix (CF)
A CF is defined as a course that terminates at a fix/waypoint followed by a specific route segment. Normal use of the CF is after an FA (course from a fix to an altitude) or a CA (course to an altitude).

So, a TF has a waypoint at both ends. A CF has a waypoint at its termination, but can start from a conditional waypoint (e.g. an altitude).

Some current FMS do not recognise TFs.

Bewildered?:confused: