Instrument: The CO analyzer for CARIBIC is a modified commercial gas chromatograph. The actual CO detection is based on the reaction of CO with hot mercuric oxide to produce CO2 and elemental mercury, which is sensed by its strong light absorption from a low-pressure mercury vapor lamp at 254 nm. Prior to detection the CO is separated on a gas chromatography column. The detection limit is better than 3 nmole/mole and sufficient to gauge CO in clean remote air masses. The repetition rate of the CO measurement is 130 s. (See also experiment and project summary.) Data format: Dataset consists of eight columns representing Date(UT), Time(UT), Longitude, Latitude, Pressure[hPa], p_height[m], Tpot[K] and CO[ppbv]. Coordinates of data probes are given explicitly while the 'boundary box' meta entries just represent the coordinates of start and destination airports. The data rows are headed by a set of text lines in CARIBIC metadata format - for interpretation cf homepage www.caribic-atmospheric.com. Special comments to this flight: New Buck hygrometer.