ON BUEKENHOUT-METZ UNITALS

Let Sigma' = PG(4, q), Sigma be a hyperplane of Sigma' and F be a regu lar spread of Sigma. Denote by pi(Sigma', Sigma, F) similar or equal t o PG(2, q(2)) the projective plane constructed using F. We give a simp le proof that if U is a Buekenhout-Metz unital of the plane pi(Sigma', Sigma, F) defined by an elliptic cone U of Sigma', then there is a re gular spread F' of Sigma such that U defines a hermitian curve of pi(S igma', Sigma, F') similar or equal to PG(2, q(2)).