Air Asia - wrong turn after take off

[Nigel C]

Interesting that they chose Melbourne due forecast storms in Sydney. I didn't have a close look at the airport forecast yesterday, but they were only predicting storms to form out west and not make it near the coast due to weak steering winds the last time I had checked.


Aside from physically pushing the control stick left, what would have made the aircraft turn left on departure? Is autopilot typically engaged that soon after take-off on A330's? And if so, why didn't the crew recognise it and correct it before they cut across the 16L extended centerline?

[Grahame Hutchison]

Listening to the ATC archive, it sounds like they had about a 40 degree variation between their true heading and what the FMC was showing. ATC questioned if they wanted to continue the flight with this navigation problem, which was via Richmond and planned route, however they requested radar vectors to try and sort things out.

[Philip Argy]

Would going to Melbourne avoid a fuel dump that would have been needed for a return to Sydney? Even allowing for nav problems, a left turn across the 16L centreline was pretty serious - I assume this will be an incident attracting ATSB investigative resource, so it will be interesting to follow.

[Rowan McKeever]

I'd imagine, as a LCC, the decision-maker wanted to make extra sure the aircraft wouldn't be stranded any longer than necessary.

[Hugh M.]

http://archive-server.liveatc.net/ys...2015-0100Z.mp3

There is the audio link for anyone interested. Incident is at 19 min 43 sec

[Philip Argy]

Thanks Hugh - that audio does not include comms with the wayward a/c - only comms with the cancelled T/O and G/A a/c. Is there another link for the (presumably) Departures frequency archive.

[David O.]

http://archive-server.liveatc.net/ys...2015-0100Z.mp3

Have a listen to this one, starts approximately similar time with ATC asking 'confirm heading'.

[Philip Argy]

Yes - that's the one - thanks, David. From about the 20 min mark you can monitor Xanadu 223 explaining problems with main nav display showing a 40 degree discrepancy with the secondary display and ATC confirming that secondary display seems to be correct. They try a couple of resets before deciding to abandon their planned route and head for Melbourne.

[Hugh Jarse]

I wonder if the IRU's were not aligned? It's happened in other aircraft before.

[Mick F]

I assume the E-Jet is similar Hugh, but the ADIRU's should take no longer than about 7mins to align. So assuming that they turned them on when they did cockpit setup, then they should have been aligned. That said, things do break! A faulty ADIRU should trigger an ECAM.

Mick