  A significant difference in Titan's ionospheric electron density is observed
between the T118 and T119 Cassini nightside flybys. These flybys had similar
geometry, occurred at the same Saturn local time and while Titan was exposed to
similar EUV and ambient magnetic field conditions. Despite these similarities,
the RPWS/LP measured density differed a factor of 5 between the passes. This
difference was present, and similar, both inbound and outbound. Two distinct
electron peaks were present during T118, at 1150 km and 1200 km, suggesting
very localised plasma production. During T118, from 1200-1350 km and below 1100
km, the lowest electron density ever observed in Titan's ionosphere are
reported. We suggest that an exceptionally low rate of particle impact
ionisation in combination with increased dynamics in the ionosphere could be
the cause. This is, however, not verified by measurements and the measured
ambient high energy particle pressure is in fact higher during T118 than during
T119.
