[snopercod]

As a former shuttle instrumentation engineer, my first question is whether all these measurements went through the same DSC [Dedicated Signal Conditioner] in the midbody.

It almost sounds like a cable burnthrough out in the wing somewhere.

I was confused about the tire pressures. If I understood correctly, they showed an increase, then went offscale low.

[steveegg]

From what I heard of Ron Dittemore's timeline, there was no mention of an increase in tire pressure; just a loss of data. I would suspect that there was both nearly-simultaneously.

[_Jim]

I was confused about the tire pressures. If I understood correctly, they showed an increase, then went offscale low.

I copied, regarding tires:

7:56 Left-main gear tire-temp
7:59 Left IB and OB Tire Temp + Press. Offscale and Low

[Jonah Hex]

Yep, that's the way I read it. Loss of temperature instrumentation data due to cable burn-through along with tire pressure increase due to temperature increase with subsequent LOS due to cable burn-through.

Although not a NASA engineer, it sounds like the left wing thermal protection system lost integrity with subsquent wing structure burn-through with disasterous results.

Not a good day...

[bribriagain]

Are there redundant sensors and wiring?

[Gracey]

I was confused about the tire pressures. If I understood correctly, they showed an increase, then went offscale low.

You must have worked at KSC Shuttle Ops turnaround. Would the tire pressure increase reentry heat from damaged leading edge tile, and then just blow (indicating no pressure)? That Columbia was full of instrumentation. I used to sit in on Shuttle change board meetings regarding same.