Three-year VLBI monitoring of PKS 0420-014

We present nine 3.6-cm VLBI observations of the optically violent variable (OVV) flat-spectrum radio quasar PKS 0420-014 taken over a period of three years (1989.32-1992.48); we also show a VLBI map from observations at 43 GH z in 1992.4. We trace jet evolution and variability with individual compone nts. We find superluminal motion with beta(app) similar to 2-14c for five j et components. Components ejected more recently seem to separate faster fro m the core. All jet components follow one common curved path within the jet . In addition to presenting the results of the VLBI monitoring, we discuss a possible correlation between component ejection and outbursts seen in the radio/optical/gamma-ray regimes. The ejection of several jet components ca n be linked to flares in the cm-light curves; the most recently ejected com ponent appeared shortly before a simultaneous radio/optical/gamma-ray flari ng. Our results are in agreement with the predictions of the lighthouse mod el of Camenzind & Krockenberger (1992), which explains the observed optical flaring. We introduce an alternative model involving a precessing binary b lack hole.