fpvdude:
Can anyone point me to any mention, in the AIP, with regards to the requirement (or lack there of) of diverting/allowing sufficent fuel for a destination airport, which deteriorates to a INTER/TEMPO below minima while in flight?
It's been a while since I've flown under Australian regs, but isn't it covered by ENR58.2.4?
"58.2.4
When weather conditions at the destination are forecast to be above the values specified at para 58.2.1, but, additionally, intermittent or temporary deteriorations in the weather below the values are forecast, provision of an alternate need not be made if sufficient additional fuel is carried to allow the aircraft to hold for:
a. 30 minutes for intermittent deterioration (INTER); and
b. 60 minutes for temporary deterioration (TEMPO)."
The AIP makes no distinction between "pre-flight" and "in-flight", so you still need to comply if the weather forecast deteriorates after you get airborne.
Snakecharma:
out of interest, when a 380 arrives in Sydney, Perth, Brisbane do they carry an alternate all the way to the destination or do they plan to a decision point and then give the alternate away if the conditions suit?
As don said, international airlines based outside Australia always
plan for an alternate. There are exceptions such as Perth, where some airlines use isolated airports rules which allow them to plan additional holding fuel in lieu of an alternate, provided the weather is above the alternate minima. If the weather is below the alternate minima, then an alternate must be planned, which can mean carrying enough fuel to divert to Adelaide or even further.
Once airborne, some airlines have rules that allow the crew to drop the alternate if it becomes obvious the aircraft will arrive at its destination with less than minimum diversion fuel. That's only allowed if certain conditions are met, such as two independent runways at the destination, weather above the alternate minima, no ATC delays, etc.