It is very common in a country such as Canada for a controller to clear an incoming American aircraft to, for example, runway 04, and the pilot read back the clearance as runway 4.
Je veľmi bežné v krajinách ako Kanada, že napr. riadiaci letovej prevádzky dá pilotovi povolenie k dráhe 04 a pilot zopakuje povolenie ako dráha 4.