Saturday, August 29, 2009

Spot the airfield: Gold Coast, Queensland

On a flight from Sydney to Brisbane in a Qantas 767-338, Air Traffic Control gave us one turn in the hold over Gold Coast airport, which created a photo opportunity for the seventh instalment of our "spot the airfield" series, where I try to spot, photograph and later identify airfields from a window seat at the back of an airliner.

Previous episodes featured Stuttgart, Dalby, Mitchell and Charleville, Lombadina, Clermont, Southport and more recently Aeropelican.

I am not instrument rated (yet), so you'll forgive the approximate description of the procedure: the airplane first flies over the navigation aid (Gold Coast VOR in our case), makes a 180-degree rate-one right turn, flies straight ahead for one minute, one more 180-degree rate-one turn, then one more minute to get back to the navaid. Each half-turn takes one minute (rate-one turn means a heading change of three degrees per second). Flying the entire holding pattern therefore takes four minutes.

The picture above was taken as we were about to complete the turn away from the navaid. The airplane bit in the bottom left corner is the trailing edge of the right wing. The Pacific Highway can be seen running across the pictures, right above the airport.

The airport's little name is YBCG, CG for Coolangatta which was the name of the airport up until 1999. It is a controlled airport, with one very long 14/32 runway and a very short 17/35 cross runway whose sole purpose is, in my opinion, to introduce confusion in the mind of student pilots trying to comply with a taxi clearance there.

It may not very obvious from the taxiway diagram in the ERSA, but a taxi clearance from the GA parking area to the run-up bay for runway 32 for example actually involves crossing runway 17/35 after taxiway Golf before turning on to Foxtrot. That's the bit marked "Runway Incursion Hotspot".

I flew into Gold Coast a few times during my PPL training. The green patch near the water in the top-right corner of the picture above is Burleigh Head, a VFR reporting point used when flying inbound from the north.

The bit of airplane here is the leading edge of the right wing. The four little vertical metal blades are vortex generators, designed to improve the airflow over the wing. That's pretty much all I know on the topic.

As to the function of the yellow piece of metal with a hole in the middle on the right, this mystery was solved by Plastic Pilot a little while ago.


Chris said...

And by a strange coincidence, I just happen to be studying vortex generators today. If I may, I'd like to describe then in the hope of improving my own understanding of the topic.

Vortex generators generate a vortex (duh!) which draws high speed airflow closer to the wings surface, re-energising the boundary layer while also making it thinner. This re-energised airflow delays boundary layer separation decreasing stall speed, and, if placed ahead of a control surface, improving control authority. Although they increase form drag slightly by sticking out in the wind, this is more than compensated for by a decrease in drag by reducing the overall boundary layer and post separation flow.

Whew! I stand happily to be corrected and improved upon.

Julien said...

Sounds an awful lot like you're studying for CPL :-) Or did you pick up advanced aerodynamics as a hobby?

sylvia said...

What a great location. I love the idea of playing spot the airfield - I keep photographing them as well but I've never thought to try to identify the planes I see.