GENERAL: Delay for freezing rain, power down for pull out of hangar. On initial descent ~ CBA, initally descended out of very high O3 air, then flew level at 28 kft into high O3, high O2, low CO, low CO2 air, then hit this layer again on the next 01:02 low point, wind blowing 62 kts at 1 kft - lots of gas exchange AO2: Initialized sample flow while fuel truck was still fueling. 21:00:49 To MAN to delay calibration ~21:16, back to AUTO for cals while level at 13 kft 01:00 +/- 5 min - high O2 noise - look at motion correction (again at 1:40 +/- 5) 03:20 calibrated right over a pollution layer MEDUSA: - During preflight, ran through an overnight (downstream) leakcheck, positions 17, 22, and 32 showed somewhat higher. Pumped down and reran through 1-16 before pullout. - After take-off tried starting prepurge, but had forgotten to clear the flask table. Powered all down/up again, cleared, and restarted prepurge. 19:42 Pos 15 and 16 had low flow. . . . - Did not get prepurge started soon enough, so flow drops before end: 19:50 P1, PBypass, and Flows start dropping while in position 27. ~ 19:52:30 While on pos 31, for some reason vstat2 to 51 (pos = ?) and CO2 and H2O dropped out, then ~ 19:53:30 vstat2 to 1, then ~ 19:55:30 vstat2 to 48 (pos = 16) and CO2 and H2O back. Momentary loss of IC Board power. Cause? 20:08 @ 40 kft, Pup = 128, Pdn = 399, Pbypass = 716, Flow = 2800. 20:38:30 Flow and Ps back up, passing through 39 kft. 21:29 PALTF = 2 kft but Radar and GGALT show 1 kft - Henry says sea level pressure is very low (28.73). SAMPLE PLAN: Dip #1 South of CBA Dip #3 Dip #5 Dip #7 Climb #9 03:14:03 done sampling at 44 kft, went back to 140/400 to see where inlet P controls - goes to 114 - will leave on for descent to get extrapolation to 47 kft. Extrapolation indicates that we need Pup of 80 to get 47 kft and Pup of 90 will work to 46 kft.