public function validate_preflight_check($data, $files, $attemptid) {
        $errors = array();
        foreach ($this->rules as $rule) {
            if ($rule->is_preflight_check_required($attemptid)) {
                $errors = $rule->validate_preflight_check($data, $files, $errors, $attemptid);
            }
        }
        return $errors;
    }