diff --git a/tools/filter-regs.js b/tools/filter-regs.js
index d4b4783..fa8fa1b 100644
--- a/tools/filter-regs.js
+++ b/tools/filter-regs.js
@@ -18,17 +18,41 @@
 //   nodejs filter-regs.js <input.csv >output.csv
 
 var reglookup = require('../public_html/registrations.js');
+var actypes = require('../public_html/db/aircraft_types/icao_aircraft_types.json');
 var csv = require('csv');
 
 var parser = csv.parse({columns: true});
 var writer = csv.stringify({header: true});
 var transformer = csv.transform(function (record, callback) {
-        if (('icao24' in record) && ('r' in record)) {
-                var computed = reglookup(record.icao24);
-                if (computed === record.r) {
-                        record.r = '';
-                } else if (computed !== null) {
-                        console.warn(record.icao24 + " computed " + computed + " but CSV data had " + record.r);
+        if ('icao24' in record) {
+                if ('r' in record && record.r != '') {
+                        var computed = reglookup(record.icao24);
+                        if (computed === record.r) {
+                                record.r = '';
+                        } else if (computed !== null) {
+                                console.warn(record.icao24 + " computed registration " + computed + " but CSV data had " + record.r);
+                        }
+                }
+
+                if ('t' in record && record.t in actypes) {
+                        if ('desc' in record && record.desc != '') {
+                                var computed_desc = actypes[record.t].desc;
+                                if (computed_desc === record.desc) {
+                                        record.desc = '';
+                                } else if (computed_desc !== undefined) {
+                                        // too noisy, the icao descriptors are very coarse and reality often disagrees
+                                        //console.warn(record.icao24 + " (" + record.t + "): computed type description " + computed_desc + " but CSV data had " + record.desc);
+                                }
+                        }
+
+                        if ('wtc' in record && record.wtc != '') {
+                                var computed_wtc = actypes[record.t].wtc;
+                                if (computed_wtc === record.wtc) {
+                                        record.wtc = '';
+                                } else if (computed_desc !== undefined) {
+                                        //console.warn(record.icao24 + " (" + record.t + "): computed type WTC " + computed_wtc + " but CSV data had " + record.wtc);
+                                }
+                        }
                 }
         }