As a CFII instructor I downloaded this to help a student work out holds. The holds they give are just as wrong as could be. They say "hold SE on the 331 bearing" or something to that effect. Well 331 isnt SE, in fact its opposite of that. So I see the word bearing and think, "ahhh so well just take the reciprocal"...and with that thought they were all wrong. When they draw out their examples, in this case "SE on the 331" they draw the pattern on the NW side. So their clearances are just totally wrong, as are the drawings. As a student this app caused me confusion so I didnt use it. As a CFII I know better now, and watched my student make several drawings correctly, only to be told theyre wrong by the app that did them wrong in the first place. Useless app, DO NOT BUY IT! It will make things so much harder. And the reality is if you can think of two numbers between 360, you can give yourself endless clearances and draw them correctly and learn this for free. Wasted money here.