All DJ and QF flights out of BNE to NZ cancelled last night.
But off went Air NZ to AKL
Air NZ have greater faith in the computer models predicting the ash cloud paths and that the ash is infact contained between FL200 and FL350. (Although I see this morning, it had risen to FL370)
No one has visually seen the ash that I know of while flying the Tasman yesterday and today. One aircraft on the AKL-SYD track yesterday, at FL180 reckoned that there was a slight discolouration in the sky to the south, however it would be hard to judge IMHO.. You can't see this ash airborne, it doesn't show up on radar, but only on infrared satellite photos.
(Although today at Auckland, I noticed while looking in the direction of the sun, there seemed to be a high level haze, but one wouldn't say that that is conclusive evidence of a ash cloud)
Most Trans-Tasman traffic has been routed via TEPEK then southerly to AKL, or are staying below FL200.
Whos right and whos "wrong"? I don't think there is a "right" and a "wrong". Air NZ have taken precautions. I'd be interested to know if they have stepped up their boroscope inspections too of the aircraft are flying to see whether or not they have picked up any ash, even though they have planned their flights below the cloud.
DJ and QF probably have less faith in the computer modelling done by the VAAC and have acted accordingly.
IMHO I personally think the ash in this case is more a economic decision than a safety issue. Yes there is a hazard, however is this ash concentration low enough that it won't cause a inflight shutdown, but rather accelerated wear and tear on engine and systems? Is it cheaper to fly at FL180 across the Tasman and operate, than put everyone up and cancel flights?