  We revisit the issue of Lagrangian irreversibility in the context of recent
results [Xu, et al., PNAS, 111, 7558 (2014)] on flight-crash events in
turbulent flows and show how extreme events in the Eulerian dissipation
statistics are related to the statistics of power-fluctuations for tracer
trajectories. Surprisingly, we find that particle trajectories in intense
dissipation zones are dominated by energy gains sharper than energy losses,
contrary to flight-crashes, through a pressure-gradient driven take-off
phenomenon. Our conclusions are rationalised by analysing data from simulations
of three-dimensional intermittent turbulence, as well as from non-intermittent
decimated flows. Lagrangian irreversibility is found to persist even in the
latter case, wherein fluctuations of the dissipation rate are shown to be
relatively mild and to follow probability distribution functions with
exponential tails.
