At at guess, because the maximum landing weight of a A330 is 187,000 kg but the maximum takeoff weight is 242,000 kg. They'd have to burn off fuel before landing or risk crushing the landing gear.<p>The A330 doesn't have fuel dumping nozzles as standard equipment so that may not have been an option.<p>Edit:<p>From a slightly dodgy source <a href="http://www.pprune.org/tech-log/117765-a330-fuel-consumption.html" rel="nofollow">http://www.pprune.org/tech-log/117765-a330-fuel-consumption....</a> they'd burn 6 tonnes on takeoff and another ~7 in the 1.5 hours before the engine failed, and approx another 7 before landing but I don't know what the consumption would be like for a single engine return.<p>That gives 20 tonnes total fuel burn. At those figures the 5:40 flight would take 41.5 tonnes of fuel, plus a bit extra.
It's too early to tell what factors went into the decision to divert to Perth. Aviation is incredibly complex and armchair speculation by people outside the industry is almost always going to get it wrong.<p>As per usual, more well-founded technical discussion on this incident is ongoing over at AV Herald: <a href="http://avherald.com/h?comment=4aac9f14&opt=0" rel="nofollow">http://avherald.com/h?comment=4aac9f14&opt=0</a>
Al Jazzera has a great exposé on the issues of quality and supply / demand for pilots in Asia. <a href="https://www.youtube.com/watch?v=qSZ-R5HdPQU" rel="nofollow">https://www.youtube.com/watch?v=qSZ-R5HdPQU</a><p>It's truly frightening, and makes me think twice when any of these airlines come up when I'm searching for flight deals.
The captain apparently informed the passengers he was praying for their survival and asked that they pray too[1]. This tells you everything you need to know about the quality of AirAsia pilots.<p>Anytime I fly in that area of the world, I make it a point to avoid Malaysian and Indonesian airlines at all costs. Fly Cathay or SingAir and their affiliates if you can. The cost premium is well worth it.<p>1)<a href="http://www.smh.com.au/business/aviation/a-boom-in-midair--then-90-scary-minutes-on-airasia-plane-that-shook-like-a-washing-machine-20170625-gwycan.html" rel="nofollow">http://www.smh.com.au/business/aviation/a-boom-in-midair--th...</a>