×
Welcome to the CPL Performance question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.
PNR & ETP wind variation
Juzzy24
Topic Author
Juzzy24 created the topic: PNR & ETP wind variation
Hi bob!
my names Justin, first time poster, long time listener!
I have a quick question for you if you could please clarify with me.
If you were given a PNR or ETP type question where you had to find the headwind or tail wind component. If for example the question said that your FPT is 020*T and the wind was 080*/30KTS
and the variation was 10* East.
would you subtract the variation from the Wind also as it’s not stated if it were True or Magnetic?
bobtait replied the topic: PNR & ETP wind variation
The wind you use must have the same reference as the FPT. If the FPT was given as True, then the wind should be True. If the FPT is given as Magnetic, then the wind should be magnetic. It is normal practice to express FPT as magnetic, so if the wind is given as magnetic, then use that in the calculation.
Sometimes in an exam, the phrase 'forecast wind' may be used. Forecast wind (or GAF wind or GPWT wind) is always True so, in that case, you would have to apply the variation to make it magnetic.
Hi Bob, just further to this question, in my last exam attempt, my arrived GS for PNR and CP calculations seems to be off resulting in incorrect times or distances. In the exam I did a month ago, all of these questions had non-round tracks and wind directions / velocities, e.g FTP 037* Wind 094*/13, which required some sort of interpolation on the ERSA gen con. Do you have any pointers for situations when the angle argument isn't on the scale? Will I round up or down, or take the average of the lower and higher angles?
