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TAF temperature and QNH
Burgerman
Topic Author
Burgerman created the topic: TAF temperature and QNH
Hi Guys,
I seem to have come across information that is contradicting and I'm just wanting clarification on it. In regards to the 4 -3 hour time slots that are given to the temp and QNH forecasts. The AIP (GEN3.5 12.16 & 12.17) specifies the times as HH, HH+3 hours, HH+6 hours, HH+9 hours where HH is the time of commencement of the TAF validity period.
I have noticed in the exam prep online prac exams that the explanation given to a question concerning a TAF and what temp or QNH to expect with a specified ETA etc. as being 90 minutes either side of this 3 hour grouping. I can see how this is perhaps operationally preferable for example: if the start time validity is a good 90 minutes or more from the time the TAF was generated.
However, I'm just wondering which option is actually correct and applies in the exam.
Richard replied the topic: Re: TAF temperature and QNH
Hi Burgerman,
Got to love AIP updates. The Nov 11 edition flags 12.16.2 and 12.17.3 as new changes. It used to be you would apply the values +/- 90 minutes each side of the 3 hour time points but it looks like they've changed it to the less complex variant. Thanks for the heads-up on that one. I'll have a word with Bob and we'll update as necessary.
As for the CASA exam, they will base their answers on the most recent regs so you would have to go by what is written in the AIP: linear interpolation between the values of HH, HH+3, HH+6 and HH+9 for QNH and Temp on the TAF.
bobtait replied the topic: Re: TAF temperature and QNH
Why am I not surprised! Two years ago I changed the Met and IREX books to reflect the 'new' presentation of QNH and temperature information. I complained loud and long about that crazy idea and now they've changed it back again to what it used to be - "Be careful what you wish for". Anyway I'll make the necessary changes to the Met and IREX books again.
Thanks Burgerman, I probably wouldn't have noticed that until much further down the road, we really appreciate your feed-back.
Burgerman replied the topic: Re: TAF temperature and QNH
No problem Bob.
I did the met exam today and got 88%. It seemed easier than I had expected however in the KDR it states TAF and ARFOR/TAF. I felt confident with all TAF and ARFOR questions in the exam so I'm not too sure what happened there!
Only AGK to go now and all the theory is done for CPL
Richard replied the topic: CPL-MET ERRATA (Re: TAF temperature and QNH)
Congratulations Burgerman on the good pass! I've just updated the errata for MET and a description of the changes for the next edition can be found here:
