Delayed roll for QF127 today?

[Philip Argy]

Happened to be at the beach when QF127 was taxiing from Alpha6 into position for a 34L departure today, and then it sat there for what seemed like an eternity until at least five a/c were queued up along Alpha.

Anyone know what caused the delayed roll - I didn't have my radio and haven't seen any comments on the Board explaining what happened.

[Nigel C]

AusCal was doing flight testing of 34L yesterday, so if it was just sitting at Alfa-6 and not lined up, then that's the most likely explanation.

[Philip Argy]

It was lined up seemingly ready to roll, and then just sat there for probably a good five minutes or more as other aircraft banked up along Alpha almost down to Lima

[NathanJ]

Restricted by 80 movements cap?

[Philip Argy]

Wouldn't expect to see an A380 lined up ready to roll and hold for that long for a movement cap - I'd expect it to hold at Alpha 6 and keep the runway clear if that was the reason.

Any other suggestions, peeps?

[Rowan McKeever]

Why not hold it on the runway for the movement cap. If that IS the reason, then nothing can land during that time anyway, so they may as well have a departure lined up ready.

[Philip Argy]

Yes - in theory that's right, but I just think it best to keep runways clear for any kind of emergency, and an A380 is not agile enough to clear quickly.

It's easy enough to hold at A6 and then taxi into position 30 seconds before the cap lifts if that's really what is going on. Better still, hold up pushbacks - why waste fuel with six in a row queued up along Alpha?

[NathanJ]

The 5-10 aircraft in the queue thing happens more than a few mornings a month. Last time I was down by the fence there was a dead bird on the runway that needed clearing before normal operations resumed. A 737 was lined up and ready to roll while the obstruction was removed and an a320 did a go around. The queue was extensive due this. Aviation!

[Daniel M]

Wouldn't expect to see an A380 lined up ready to roll and hold for that long for a movement cap - I'd expect it to hold at Alpha 6 and keep the runway clear if that was the reason.

Any other suggestions, peeps?

Asks question but then dismisses possible answers.

Smh

[Philip Argy]

Not dismissing at all, Daniel - it's entirely plausible if not quite likely, but I'm just exploring if there was any other cause that someone on this board may know about, which is often the case :)

[Rowan McKeever]

Yes - in theory that's right, but I just think it best to keep runways clear for any kind of emergency, and an A380 is not agile enough to clear quickly.

It's easy enough to hold at A6 and then taxi into position 30 seconds before the cap lifts if that's really what is going on. Better still, hold up pushbacks - why waste fuel with six in a row queued up along Alpha?

Not only in theory. The movement cap is managed, for arriving aircraft, through sequencing and extended tracks. IF it was the movement cap at play, and the A380 was held on the threshold for an extended period, then ATC obviously knew there were no arrivals sequenced to land before the A380 would depart.

In a worst case scenario, i.e. an inbound emergency, the A380 would either be asked to vacate or given a takeoff clearance. And, in that case, there would be plenty of time for this to happen while the emergency was positioned out of sequence for landing.

[Mick F]

I'm sure if an emergency eventuated, there would be enough time to clear an aircraft from the runway. Emergency landings don't just happen with 30 seconds notice (99.9% of the time).

I'm sure the boys and girls up that tower know what they're doing Philip.

Mick

[Tom Lohdan]

Phillip, have you tried listening to the YSSY ATC archive?

http://www.liveatc.net/archive.php

[Philip Argy]

Great suggestion Tom - I should have thought of that. ATC archive revealed an urgent medivac flight was given taxi/take off priority on 34L from B6 after the A380 had just been given permission to taxi from A6 and line up - all explained!