  Aims. Every 5.5 years eta Car's light curve and spectrum change remarkably
across all observed wavelength bands. We compare the recent spectroscopic event
in mid-2014 to the events in 2003 and 2009 and investigate long-term trends.
Methods. Eta Car was observed with HST STIS, VLT UVES, and CTIO 1.5m CHIRON for
a period of more than two years in 2012-2015. Archival observations with these
instruments cover three orbital cycles. Results. Important spectroscopic
diagnostics show significant changes in 2014 compared to previous events. While
the timing of the first HeII 4686 flash was remarkably similar to previous
events, the HeII equivalent widths were slightly larger and the line flux
increased compared to 2003. The second HeII peak occurred at about the same
phase as in 2009, but was stronger. The HeI line flux grew in 2009-2014
compared to 1998-2003. On the other hand, Halpha and FeII lines show the
smallest emission strengths ever observed. Conclusions. The basic character of
the spectroscopic events has changed in the past 2-3 cycles; ionizing UV
radiation dramatically weakened during each pre-2014 event but not in 2014. The
strengthening of HeI emission and the weakening of the lower-excitation wind
features in our direct line of sight implies a substantial change in the
physical parameters of the emitting regions. The polar spectrum at FOS4 shows
less changes in the broad wind emission lines, which may be explained by the
latitude-dependent wind structure of eta Car. The quick and strong recovery of
the HeII emission in 2014 supports a scenario, in which the wind-wind shock may
not have completely collapsed as was proposed for previous events. All this may
be the consequence of just one elementary change, namely a strong decrease in
the primary's mass-loss rate.
