Originally Posted by
KRviator
Yes.
Per AIP ENR 11.7.1.3, you are using the GAF to determine destination weather, however, 11.7.1.3 requires you to use an aerodrome forecast which is referenced to a TAF. Cessnock has no TAF so you must plan an alternate to Maitland, if Maitland itself does not require an alternate due weather.
It's a ridiculous situation where you cannot use the GAF for arrival weather, but so long as that AIP says "aerodrome forecast" you have to have a valid TAF to be able to determine if the weather will be above the Alternate Minima.
I'd like to know what idiot wrote that such that I can't use the GAF!
The AIP actually conflicts this statement though. Although i do see your reference
In ENR 1.10 1.2.1 it states forecast information obtained must include aerodrome forecast etc. etc.
However, further down, it states " For a flight to an aerodrome where an IAP does not exist, the minimum forecast is a GAF". Therfore, since Cessnock has no IAP, the minimum forecast is a GAF.
Additionally, a TAF at Cessnock would be useless
for alternate planning as since there is no IAP , as you must consider weather over the last route segment, which almost always will be outside the 5nm region of a TAF, thus requiring the GAF to be considered. I find it hard to believe there could be influential IMC weather on an aerodrome TAF, that isnt mirrored on the neighboring GAF since a GAF by definition must be more consiervative anyway.
mmm345, thank you for putting the time into this, I really appreciate it.
So one last question - In your example, I follow it all, but isn't the critical link still the airport itself? Say I depart to Cessnock from Bankstown, on a beautiful clear day, just after dawn, in winter, no fuel for an alternate, No cloud on the GAF at LSALT plus 500 for the final segment, therefore I can navigate happily but when I get to Cessnock there is a fog bank. For a reason like this scenario is why I interpret that General statement at the start of the Alternate section of AIP to be if there is no TAF you need an alternate.
Taking it to an extreme, say I was chartered to fly an A380 from Sydney to Cessnock (yes I know the airfield wouldn't take an A380 but its just a hypothetical, I couldn't imagine doing the flight without having an alternate that has a valid TAF.
I see your viewpoint and from an airmanship point i agree with you, however as you have both pointed out earlier, airmamhip is different to legal requirements.
ENR 1.10 states that the minimum forecast to a negative IAP destination is a GAF, i cant really see why they would write that if you actually needed an alternate whenever there wasnt a TAF because that would just be contradicting exactly what they write in ENR 1.10 ( Note. the statement in the alternate section for weather begins with " For an aerodrome with an IAP" which isnt Cessnock.
Additionally, i acknowledge you point about Fog and to be honest with you, if i was PIC conducting an early morning sunny winter flight to Cessnock, i would carry alternate fuel from an airmanship persepctive and what i know from local knowledge of actually flying there.
However, I dont see how there could be Fog at cessnock, of which isnt reflected on a GAF which is meant to reflect the weather conditions within a much larger area than the 5 miles of a TAF. If there is Fog at Cessnock, one would see this on the GAF that includes the Cessnock area and thus plan an alternate as vis/ cloud would be below 8km and LSALT +5 etc....