  Let Alice, Bob, and Charlie initially share an arbitrary fermionic
three-qubit pure state, whose three-tangle is $\tau_3^{(0)}$. It is shown
within the single-mode approximation that if one party among the three of them
moves with a uniform acceleration with respect to the other parties, the
three-tangle reduces to $\tau_3^{(0)} \cos^2 r$, where $r$ denotes a
statistical factor in Fermi-Dirac statistics.
