## TMG and HDG alternate method

• Simklay
• Topic Author

### Simklay created the topic: TMG and HDG alternate method

Hi guys,

Due to COVID-19 and quarantining etc, I've found myself with some spare time. I've been meaning to post this for A LONG TIME.
I'm a Flight Instructor and currently studying ANAV at the moment. I keep coming back to this method I devised when I was studying BAK/PPL/CPL navigation, many years ago.
The method in Bob's amazing books are great, but I did make mistakes early on as using the circle and square method for HDG/TMG (not sure if this method is still in the books) sometimes saw me plug in the incorrect values, as I was mainly struggling with the orientation.
To help ensure I didn't stuff up my HDG and TMG calculations moving forward (as it was simple enough but frustrating to get them wrong every now and again), I came up with this. Even today, I'm still using it for ATPL NAV for finding in flight winds.
It may look complex but it really isn't, it just depends on your mind I suppose, some people love it, some people hate it. It's just another way of doing it.

The JPEG is an attachement below.
Just fill in the values given in the question, for example:
If you're given TMG, plot that in the middle box ALWAYS.
If you're given HDG and it is larger that the TMG, use the right HDG box (and this denotes you're experiecing left drift - ie left wing forward) and look at the difference between TMG and the HDG to find the drift angle.
If you're given TMG and drift angle, use the appropriately labelled drift circle to find the HDG.
If your given HDG and drift angle, use the appropriate HDG and drift box to find the TMG.

By working linearly, if you move to the right, ADD.
If you move to the left, SUBTRACT, just like the actual alteration of HDG in an aircraft.

Hope this helps someone!
- Simon.