You might get away with this, provided the spurious blank lines don't turn up just after the ZONE 001 in the third section of your example dataset.

#! perl -slw
use strict;

my $data = do{ local $/; <DATA> };

print "'$1'" while $data =~ m[
    (
        ^(?:DES|TN)
        .+?
        (?:^DATE|ZONE)
        .+\n\s*(?:\n|$)
    )
]gsx;
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