I'm a "semi-local" AF pilot i.e. have been long tour TDY for upgrade training at Randolph twice, but I'm too much of a second class citizen to get the hook-up of permanent duty station to bona fide civilization...so they stuck me doing the same job 130NM to the west in g-d Azkaban, via US HWY 90 aka the Trail of Tears. I digress.
At any rate, here's the deal: That Alert area is for the Seguin Aux Field, Charlie Brown is the name of the RSU (runway supervisory unit). The airspace is yours to transit, but knowing the local pattern ops will help you stay clear of conflict.
Seguin is the T-38 aux field. KBAZ accomodates the T-6s (used to be KSSF exclusively). See attached MACA brochure for a "sketch" of the pattern flow between home plate and Seguin Aux. It's not particularly accurate in the way our FOUO inflight guides are, but it will get you a good enough idea. Recognize we don't fly nights locally at Randolph, and AF aux fields in primary training programs are always daytime only anyways. As such Seguin ops are daytime only. They're also fairly sparse compared to T-6 ops in volume. Most of the time, seguin is crickets.
Your conflicts are the transit areas from RND into the Seguin pattern, latter which is a 9 mile box to the east of the runway (the depiction in the sectional is misleading, there's only one runway). So, stay west of the extended centerline and you're good to go. Nothing is going on above 3000'MSL, so if transiting from the eastern quadrants, stay above that altitude until past the extended centerline and then descend into E70.
Where you DONT want to be is within an L-shaped ground track starting from the runway thresholds up 4NM and bending towards 9NM in length, at 1000AGL and 1500/1800AGL. Those are the st-in and initial tracks respectively. An additional shelf occurs at 2000-2500AGL for the emergency high pattern. This is the significance of 3000MSL as the magic number for no conflict.
If you broadcast on their VHF, all that happens is the RSU hears you but the T-38s don't, because they're probably on ops freq, unless the new standards have them monitoring Charlie brown victor. They're all squawking 1200 or 0222. T-38s are TCAS cape, so we can see you when you're squawking. We don't squirt RA in the pattern, otherwise the damn thing goes off all the time. We are strictly TA silent, but we still get a TA call for somebody like you crossing. So we have OK SA with the fishfinder. Still, no reason for ya to cross those approach corridors below 3k MSL during bankers hours M-F. Once over Seguin you should be able to descend no problem into your destination. Give a wing rock up there if you're ever overhead and see a couple Talons below ya at 300KCAS. Safe flight!
). Outlying Aux fields can be completely empty or could have several aircraft doing all sorts of profiles.
