NH880 departure 28AUG

[James R]

Good evening,

The QF25 this evening departed 16R and followed what looks like a standard DEENA 7 departure, with an eventual right turn up over the inner west / western suburbs. Minutes later the NH880 followed the same track but instead turned left, looping back around and crossing the coast around Little Bay then northward between YSSY and the city.

Is this a non-standard track for 16R departure and if so, any reason why it would have travelled as such? The later CX and others took the usual track.

Cheers.

[James Smith]

Hi James,

It is not too unusual to see ATC cancel the SID and direct an aircraft to turn left and track direct to waypoint Richmond, often flying close to, or back over the airport. It looks as though there were three aircraft today that did this, looking closely at the 16R logs. It is not too regular as this track will conflict with any departures from 16L.

Prior to parallel runway operations traffic to the west and north west departing off the old 16 used to more regularly turn left and track back over the airport.

From my guess this can be due to the aircraft ahead on the same track climbing at a slower rate and is a way for the following aircraft to have unrestricted climb. This would have been the case with a slower climbing 744 in front of a faster climbing 789.

At waypoint Tammi, inbound traffic from the south west and outbound traffic to the west or north west pass each other with the descending aircraft having to be at or below 9,000 feet and the climbing aircraft 10,000 feet or above. If a descending aircraft was not able to meet this requirement, ATC could have kept the outbound aircraft out of the way by turning it left.

There could be other reasons as well. I hope this helps.

[James R]

Many thanks for the detailed response James, much appreciated.