As pointed out
Barry / Dynamic, this is now an 'old' system - (despite all the
PR about being worlds leading technology and all that kind of fluffy stuff used to win elections) - as such it has been adapted in different locations tio make it work, usually by differing procedures.
As
SM4 points out in his/her sector they like to get you to squawk A1200. However, in my sector which is only 30nm wide we leave you on the code for our own situational awareness - this is due to the number of radar tracks operating close to CTA with a lot of training aircraft included as well as the ability to quickly grab you back if you need to get another clearance / diversion etc. Some locations do it different due to various limitations such as radar coverage as mentioned above.
There are 4096 possible codes (8 digits on transponder x 4 digits tf. 8 to the 4th power), so there are not enough to give each aircraft it's own permanent skin code, as well as leaving enough reserved for itinerant (International) aircraft.
However with the eventual 100% coverage using ADS-B, assuming the government subsidise the installation of the aircraft equipment (which actually makes economic sense for all concerned) for all Australian GA/RAA capable aircraft, I am led to understand there will be enough codes for each aircraft to have a permananent skin code.
Whilst convenient, and a great boost for safety, it will of course raise some privacy issues.
And it is probably a long way off yet.
EDIT: It appears Dick's supporting of
www.bindook.com was to no avail - noticed that:
Bindook.com This domain name expired on Apr 14, 2005.
However, in a somewhat freudian manner it refers the viewer to the following 'related' links:
Trash cans
Garbage cans
Trash can
Garbage can
Trash bin
Oh the
irony!