This should work according to your example:

#!/usr/bin/perl

use warnings;
use strict;

my $string = "UFOFH 33603 01231 /0000 0024/ 1024/ 2025/ 3027/ 4030/ 50
+25/ 6028/ 7060/ 8081/ 9098/ 0110/ 1107/ 2106/ 3102/ 4080/ 5065/ 6057/
+";

if ( $string =~ m#UFOFH ([\d/]{5}\s?){4,27}# ) {
    print "$string\n";
}
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Update: I updated the regexp to be a little prettier. Need more coffee...