Well, again one to read up on in the Starports book, guys...
For Class A, B or C... (Class B or C may not have a highport)
Firstly, you'd contact Traffic and Flight Control, whos operators would put you into a holding orbit until a space freed up. While you wait, a customs cutter might challenge you to scan and search your ship. Once space is available, you get assigned a flight corridor through which you would pilot your ship to either the downport or the highport as you wished. I'd expect a beacon to be turned on ready for you so that your flight systems could lock onto your assigned pad. At all times, I'd expect verbal instructions with broadcast information to back it up.
For Class D, As above, but no choice of a Highport (obviously), but at least you have a verbal talkdown and maybe a beacon to guide you to the Downport. If you're using an aerodynamic ship, you also get a landing strip.
Class E
Good luck... you MAY be able to raise them on the comms to find out if there's a free pad...
In all cases, there'll only be one downport per planet - the SPA isn't going to waste money on multiple ports and you need special landing pads to take the high tonnage involved in a ship - if they had the money to upgrade the downport, they'd upgrade the existing facilities, not build another shed and tarmac - much better to actually pay for an actual fire-fighting or repair facilility. In an emergency, a sub-400 ton craft could probably use a Small Craft landing site, but remember that you'd not be subject to Imperial Law, but the local law, so anything up to seizure of your craft may be applicable if you have locally illegal goods on board (or if you failed to get permission first in some cultures).
Where the weather is bad (obviously applicable to downports only), if it's too bad, expect a holding orbit, if not then you'd probably be given the choice. If you're low on fuel, I'm sure they would be happy to provide a fuel tanker to come and top you up for a fee, but at least you'd be ok until the weather clears or a pad opens up (quite possibly related). I can't see a 200dton spaceship being thrown around too heavily though (although it might cause a drift when landing). Most of the problems caused by weather on aircraft like the Boeing 747 (400 tons) is the speed it's moving and that it's designed to be aerodynamic going forwards only. If you're relying on an aerodynamic landing, then you're going to have to wait for the weather to be sensible before attempting a landing.
Taking off, if it's aerodynamic then a high headwind is preferable... otherwise it shouldn't matter, providing it's not gusting in either case - a constant wind is far easier to deal with.
As for transponders, if you didn't have one, you'd probably not have gotten close enough to attempt a landing - an unknown craft would have been challenged long before attaining orbit in all but the most remote systems. In the event that your transponder is, indeed, offline, then the customs cutter would probably act as a guide for you (partly so the Flight Control people know where you are, but also so that if you try any funny stuff, there's an armed cutter right beside you...). Remember that starports are delicate things and Imperial property... put together, means that they'll be paranoid about it...
Rust: lol... I love it!
