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We report the results of multi-epoch VLBA observations of the 22.2GHz watermaser emission associated with the "water fountain" IRAS 18286-0959. We suggestthat this object is the second example of a highly collimated bipolarprecessing outflow traced by water maser emission, the other is W43A. Thedetected water emission peaks are distributed over a velocity range from-50km/s to 150km/s. The spatial distribution of over 70% of the identifiedmaser features is found to be highly collimated along a spiral jet (jet 1)extended southeast to northwest, the remaining features appear to trace anotherspiral jet (jet 2) with a different orientation. The two jets form a"double-helix" pattern which lies across ~200 milliarcseconds. The maserdistribution is reasonably fit by a model consisting of two bipolar precessingjets. The 3D velocities of jet 1 and jet 2 are derived to be 138km/s and99km/s, respectively. The precession period of jet 1 is about 56 years. For jet2, three possible models are tested and they give different values for thekinematic parameters. We propose that the appearance of two jets is the resultof a single driving source with significant proper motion.

High Velocity Precessing Jets from the Water Fountain IRAS 18286-0959 Revealed by VLBA Observations