First Navs

Here we are... The navs have started!

Olotea Harbour

I've done already 2 small navs. The first two navs are dual, followed by two solo navs which means that next time I'll be exploring NZ solo...

HN-Karapiro-Kopuarahi-Raglan-HN

The first nav is an easy one just to become familiar with the CTC procedures concerning navigation planning. Hopefully during this nav, the wind would be slightly different from the forecasted wind and you would then learn the standard closing angle methode. A very efficient method when you're experiencing a drift which leads you off track.

This method is pretty straight forward:

Let say, your heading is 360°M but your ground track is 005°M. It means that the track error angle is 5°. 

When you find it out, you have to measure how NM off track you are, using your thumb or any other finger you know the lenth in NM. In this example you are 5NM off track.

The first thing to do is to kill the error. You'll then fly on the 355°M heading which will make you fly parrallel to your ground planned track.

Then, you will fly to an heading of 30° less, so 325° during 5 minutes. 5 minutes because you were 5NM off track. If you had been 2NM off track you would have flown on 325° for 2 minutes.  When the 5 minutes are elapsed, you can go back on your planned heading, 360°M.

Easy method but really efficient and helpfull.

HN-Karapiro-Kinloh-Taharoa-HN

The second navigation is supposed to teach you how to divert on a correct heading with a good ETA. The method taught is quiet easy while you are confortably seated on the ground but in the aircraft it can be quiet hard to think and make easy calculations.

The method is to choose a point from where your diversion will start. Then you will draw on your map a line joining the diversion point to your destination. You'll at that point be able to determine roughly the True track and then the Magnetic track of your new leg.

Once you've done that you have to figure out the drift you'll experience to select the correct heading and also figure out your new groundspeed to establish a good ETA.

For both heading and groundspeed we use the clock wind method:

Your Track is 005°M and the wind is coming from 350° for 20kt. 

There is a 15° difference between the nose of your aircraft and the wind. We have then to refer to the clock to see how much drift we are going to experience. 15° correspond to a quarter of the wind's strengh so 5. You just find out that the wind will blow you 5° off track to the right. So to fly your planned track your heading must be 360°.

Now for the grounspeed, it's quiet similar, but we have to calculate the angle between the wind and the leading edge of your wing. In this example there is a 75° difference. As previously you refer to the clock. The angle is greater than 60° so you take the entire strengh of the wind, 20kt is this case. Your new groundspeed will then be your TAS minus the strengh of the wind. You'll then be able to caluclate a new ETA.

Raglan Harbour

 Next step: solo navs and also my PPL conversion...