diff --git a/src/Airports/airport.cxx b/src/Airports/airport.cxx
index c8be10102..5b89c886e 100644
--- a/src/Airports/airport.cxx
+++ b/src/Airports/airport.cxx
@@ -724,7 +724,7 @@ void FGAirport::validateILSData()
     
   SGPath path;
   if (!XMLLoader::findAirportData(ident(), "ils", path)) {
-    return; // no XML tower data
+    return; // no XML ILS data
   }
   
   try {
diff --git a/src/Navaids/NavDataCache.cxx b/src/Navaids/NavDataCache.cxx
index 79989c57d..d74eaf3fd 100644
--- a/src/Navaids/NavDataCache.cxx
+++ b/src/Navaids/NavDataCache.cxx
@@ -133,7 +133,7 @@ static string cleanRunwayNo(const string& aRwyNo)
   }
 
   string result(aRwyNo);
-  // canonicalise runway ident
+  // canonicalise runway ident to two digits and one optional uppercase letter
   if ((aRwyNo.size() == 1) || !isdigit(aRwyNo[1])) {
     result = "0" + aRwyNo;
   }