I think all the problems related to P20. After starting P34 I kept getting 525 alarms (SV/RR LOS > 3 deg). F 06 49 would also pop up, and I don't know what "delta SV" is (or should be), as well as what delta R or delta V should be. Should I accept? Reject? Recycle? An occasional F 06 05 displayed. Lots of stuff. I was hoping the expanded description in an AOH might help me out. But it all tells me I was way off somewhere, which is why I abandoned that attempt and went back to the undocking and started over.
"SV/RR LOS > 3 deg" means that the direction to the CSM as the LGC knows it differs by more than 3 degrees than the direction that the RR is pointing to. So either LGC or RR is wrong, in the LGC it would be the state vector, with the RR it would be a side lobe lock-on. Delta SV means, when the LGC takes a mark using RR range and range rate data, the state vector is going to be updated in the LGC by a certain amount. If that update exceeds a threshold (5000 ft or 5 ft/s) it does not automatically incorporates the RR data but shows you that amount that the state vector is going to be updated by (N49, units are 0.1 NM and 0.1 ft/s). So it then gives you a choice for the update. If the update is too high then it could be a bad mark, or your initial state vectors are just quite inaccurate.
I've always felt that the Apollo 9 rendezvous stands or falls with the undocking. They didn't run P47 for undocking, but undocking does cause a DV on both CSM or LM. So it is very important that after undocking you fire the thrusters to have station keeping at the desired distance, I think 50 ft or so. The state vectors in CMC and LGC for CSM and LM are identical until you do the V84 for the CSM sep maneuver. If you just let the CSM and LM drift apart after undocking you are starting off with a not insignificant state vector difference, that could easily cause your P20 issues.
On that note, I just finished the phasing burn. Just wanted to check that I did this correctly...
At phase TIG - 2 min when the checklist says "Trim AGS errors to 0", I rolled the LM to 000, and tweaked the pitch and yaw to center the FDAI needles. At this point the CSM was centered in the boresight just before ignition, FDAI RPY 000,285,000, slightly different than the PAD pitch of 283. Does that orientation sound correct?
Yeah, good enough. The AGS isn't a very clever system. If you give it automatic attitude control for a burn and your current attitude is far away from the burn attitude, you get really high attitude rates. So what you want to do there is to get to the burn attitude manually (that's the "Trim AGS errors to 0") and only then give the AGS automatic control, so that it doesn't have do a big maneuver.
And then starting P76 in the CSM, the checklist asks to enter "desired" dVs and TIG. Do we enter the LM phasing burn dVs and TIG?
Yes, P76 (and V84 in the LGC, which does the same thing) is how you tell your computer that the other vehicle has done a maneuver. So you enter the DV and TIG of the maneuver. If you want to get fancy, instead of using the TIG from the PAD you can see that e.g. the burn took 26 seconds so you add half of that to the TIG. P76/V84 "simulate" the burn as an instant velocity change, so using a TIG of halfway into the burn gives you a bit more accurate state vector. But it's not strictly required, after one or two marks with sextant or RR this error would already be cancelled out. And the CSM sep maneuver is short enough that you should just use the actual TIG and not do any math there haha.