Course and heading

[expat]

Short and simple, what is the difference between the two. For example when on an ILS approach, they are the same value?

Matt

[Nav]

'Heading' is the direction in which you want the aircraft to fly. 'Course' is the 'heading' on which you want the navigation system to approach a given aid (VOR, beacon, or runway).

As an example, suppose you are on autopilot and want to intercept the line of a runway which runs at say 90 degrees. You would set 'Course' to 90 degrees, but 'Heading' to say 50 degrees, and fire up the ILS.

The systems will then fly a 'heading' of 50 degrees until the aircraft arrives at the 'course' to the runway - then they will switch off 'heading hold' and follow the ILS beam. In other words, fly you along two sides of a triangle.

There is usually no need for the two to agree. Once you're established on the ILS, though, it's a good idea to set 'heading hold' to the runway heading - helps if you get told to 'go around'.

[FridayChild]

The heading is the direction your aircraft is pointed to.
The course is the direction the runway is pointed to.
When flying an ILS approach, you set the heading to whatever is necessary to intercept the localizer (the sharpest the angle you intercept it, the better - usually you'll be vectored by ATC) and the course to the runway orientation (not always exactly matching the runway number: for example a "runway 9L" could be set to a course of, say, 89 degrees), but this second operation is just made to give you a visual idea (on the Horizontal Situation Indicator) of where you are and where the runway is. When the aircraft will intercept the localizer, if APP is armed, the autopilot will take over the heading.

[expat]

Thanks Guys, nice and simple, just how I like it

[Brett_Henderson]

Quick definition of these often misused terms.

Course: The direction you WANT to go.

Heading: The direction you are pointed.

Track: The direction you ARE going.

Bearing: The direction relative to YOU.

EXAMPLE: You want to get from A to B

[expat]

Bret,

Thanks, a picture says a 1000 words.

Matt

[Brett_Henderson]

You're welcome  ;D

Sometimes it gets confusing.. especially flying ILS in the sim (no real instruction). Flying an ILS lined up with the runway, you need to fly a heading that will hold the "approach" course. Prior to that (and this where people mix the terminology) you need to fly a heading that will hold an "intercept" course (not fly a heading to a course (approach or otherwise)).

In real IFR flying.. more times than not, ATC will give you a best-guess for a heading, but it's up to you to interpret that as a course (direct-to.. intercept.. approach.. etc.) Afterall.. you've got that approach plate right there in front of you  ;)

Even commonly accepted ATC practices mix terminologies to keep communications brief. If the tower tells you, "cleared for take-off fly runway heading" when there's a stiff crosswind.. He wants you to fly straight out (keeping lined up with the runway). Obviously, if you just hold a runway heading (like he told you to (technically)).. you'll drift off and get yelled at  :-[

What he SHOULD say is, "Fly a heading to hold departure-end course".

Confused yet ?

[xtp]

A better definition of course is desired track.

[beaky]

Bret,

Thanks, a picture says a 1000 words.

Matt

Hhowever, it's much easier to hold tthe correct heading to track your desired course if you are not flying knife-edge...

[Brett_Henderson]

Hhowever, it's much easier to hold tthe correct heading to track your desired course if you are not flying knife-edge...
 

LOL..  well.. it'd be even tougher holding altitude  

Sorry... that was the handiest, airplane clipart  :-[

[FridayChild]

Sorry for my lack of precision. Looks like I'll have to study a bit.