Hello.
My query is in relation to question 59 on the PPL practice exam (PPL text book, issue 15). The question asks this:
Determine Density Height
PH: 4000ft
OAT: 17

This is my working
DH = (17-(15-8))x120 + PH
DH = 1200 + 4000
DH = 6200

The answer states that the density height should be 6000ft. Is there something wrong in my working or is the answer published incorrect?
Thanks,
Tom

Hi Tom,

Your working is spot on but you made a mistake in your final step. You're going to kick yourself but check your sums in that last bit: 1200 + 4000 is not 6200

The answer is actually 5200 ft which is option (c) and that's the answer in the book too.

Cheers,

Rich

Wow. How did I manage to make that mistake!!
Thanks for your reply, much appreciated. The only thing that I would like to point out is the options for that question go as follows:
(b) 4000ft
(c) 5200ft
(c) 6000ft
(d) 6200ft

Another reason I got confused by the answer given there are 2 (c) options and no (a)!!
Thanks for your help - I've got my ppl theory exam tomorrow...here's hoping I can learn how to add by then!
Tom

Now it's my turn to say "Wow, how did I miss that!" Thanks for the heads-up - I'll get it into the errata.

Good luck tomorrow and let us know how you get on.

Cheers,

Rich
.

Had my PPL exam today and passed with 80%! And I got my density height question correct!!!
Tom

Great Job Tom - congratulations! That really is excellent news!

Onwards and upwards mate, now the learning really begins

Cheers,

Rich

Thanks Richard! Can't wait to really start getting into my navs! And CPL theory is only just around the corner!
Tom