Hey,
This is actually more of a met question, but studying for irex, so using the BT IREX book.
Q5 pg 167 is asking about alternates etc.
The alt minima for Gladstone is 1331' with ATIS and 4.4k vis
The relevant part of the TAF for the question has SCT010 SCT040 BKN014
So the answer in the book is an alt is not required based on the BKN014 being higher than the alt min of 1331'
BUT AIP ENR 1.1 8.8.2.1 says SCT + SCT = BKN
SO do those two scattered's = BKN at 010 or 040? I would have assumed you take the lowest base??
Found another one. IREX book pg 199 Q20.
TAF IS: VIS 6000 SCT010 FEW008
which is said to be below the alt minima of 1200ft ceiling, 6km vis? the vis is AT 6km so OK. So does this time AIP ENR1.1 8.8.2.1 come into effect, but not with the question above?
When the AIP says FEW + FEW = BKN, it means that BOTH cloud layers are below the alternate minimum. If one is below the minimum and one is above the minimum, the one above the minimum is ignored. It is only cloud forecast below the minimum that is considered when planning an alternate. Also, the AIP says "below the minimum", not "at or below the minimum. If the cloud is AT the minimum it is not considered, it must be BELOW the minimum.
ok, that definately clears up the cloud problem. thank you for the reply.
any ideas on the visibility question? is it AT or also BELOW?
