What caused this hold at T-5:00min?

[Tim13]

000000.030: LCC: RS Countdown Hold Flag is on
000000.030: LCC: ME1 Pad Data Path Fail Hold
000000.050: LCC: RS Countdown Hold Flag is on
000000.050: LCC: ME1 Pad Data Path Fail Hold
000000.070: LCC: RS Countdown Hold Flag is on
000000.070: LCC: ME1 Pad Data Path Fail Hold
000000.085: LCC: RS Countdown Hold Flag is on
000000.085: LCC: ME1 Pad Data Path Fail Hold
000000.095: LCC: RS Countdown Hold Flag is on
000000.095: LCC: ME1 Pad Data Path Fail Hold
000000.146: LCC: RS Countdown Hold Flag is on
000000.146: LCC: ME1 Pad Data Path Fail Hold

 

[Urwumpe]

Did you check the switch positions before launch?

 

[DaveS]

Did you check the switch positions before launch?

My thinking right now is that he forgot to perform the APU PRE START and APU START procedures. Those can be found in section 1 of the Ascent Checklist.

 

[Urwumpe]

My thinking right now is that he forgot to perform the APU PRE START and APU START procedures. Those can be found in section 1 of the Ascent Checklist.

I suspected, its rather the old problem with the MPS AC power switches on R2 having the wrong position in a scenario. But yes, something like that.

 

[Tim13]

@Urwumpe
--I did follow a condensed checklist that I've been developing, that worked in the pre-compiled v4.2.

@Dave
--I completed both the APU pre-start, and the APU start. I was actually running the audio from an Endeavour launch, and my AUP pre-start, and start, coincided with the audio....kinda cool.

What I did was take the STS-126 launch scenario, and work it backwards in time, to reset the mandatory switches, so that the scenario could be then used with the checklists.

Tim

---------- Post added at 06:35 PM ---------- Previous post was at 06:20 PM ----------

Does anyone on the team have a launch scenario that has all of the switches properly set as they should be at crew ingress?

 

[GLS]

The hold is caused by the GPCs not seeing (all) the data from the SSMEs... why is that? :idk:

What I did was take the STS-126 launch scenario, and work it backwards in time, to reset the mandatory switches, so that the scenario could be then used with the checklists.

OK, so you probably messed up the positions of SSME power switches and/or EIU power switches. They should all be on from like T-11 hours (or even earlier), so for now there is no need to play with them.

Does anyone on the team have a launch scenario that has all of the switches properly set as they should be at crew ingress?

We barely have SSU running from T-9 minutes, so anything before that time is almost certainly "not supported".

 

[Tim13]

The hold is caused by the GPCs not seeing (all) the data from the SSMEs... why is that? :idk:



OK, so you probably messed up the positions of SSME power switches and/or EIU power switches. They should all be on from like T-11 hours (or even earlier), so for now there is no need to play with them.

That might be it. In the scenario I'm working on, I have the power SSME power switches off, with a call to turn them on during the "pre T-32 minute" portion of the checklist.

Also, when it comes to the APU prestart, and the APU start, how much time do you have to get that done before a hold is initiated? The CL's call for T-6:15, and T-5:00. On the actual audio, these events are initiated on time. Does SSU require them to be completed by a certain time in the countdown?

Tim

 

[GLS]

That might be it. In the scenario I'm working on, I have the power SSME power switches off, with a call to turn them on during the "pre T-32 minute" portion of the checklist.

I doubt that "T-32 minutes" is right, as the SSME controllers need to be on for PSN-1 before tanking, and that starts at T-6 hours, so....

Also, when it comes to the APU prestart, and the APU start, how much time do you have to get that done before a hold is initiated? The CL's call for T-6:15, and T-5:00. On the actual audio, these events are initiated on time. Does SSU require them to be completed by a certain time in the countdown?

Tim

Not sure if I added checks for the APU prestart (of if there are any), but the APUs need to be on, and the hydraulic pressure up, by T-4m15s I think, or a hold at T-4m will be added.

 

[Tim13]

T-4m15s is good to know. If the APU start is done on time at T-5m, then there is no time to dilly dally, to make sure the APU's fire, and the HYD PRESS gets in the green.

Thanks for the info!

Tim

 

[DaveS]

Not sure if I added checks for the APU prestart (of if there are any), but the APUs need to be on, and the hydraulic pressure up, by T-4m15s I think, or a hold at T-4m will be added.

APU prestart does have a GLS check tied to it at T-5:25. So the hold would be at T-5:00 until the proper switches on R2 are in the correct positions and the hold cleared by CGLS.

 

[Tim13]

That's good info about the pre-start.

Also, going from the 4.2 pre-compiled build to the current build, I noticed the switches on panel R1 now work. Are they coded to do anything, or are they just animated for now?

Tim

 

[GLS]

Also, going from the 4.2 pre-compiled build to the current build, I noticed the switches on panel R1 now work. Are they coded to do anything, or are they just animated for now?

Tim

For now they just move. :shrug:
You can see the major changes from SSU 4.2 in the Changelog.txt file in the docs folder.