diff --git a/src/Airports/GenAirports850/elevations.cxx b/src/Airports/GenAirports850/elevations.cxx
index 9eac44cd..5607c290 100644
--- a/src/Airports/GenAirports850/elevations.cxx
+++ b/src/Airports/GenAirports850/elevations.cxx
@@ -47,7 +47,7 @@ double tgAverageElevation( const std::string &root, const string_list elev_src,
     std::vector<SGGeod> points = points_source;
 
     // just bail if no work to do
-    if ( points.size() == 0 ) {
+    if ( points.empty() ) {
         return 0.0;
     }
 
@@ -126,4 +126,4 @@ double tgAverageElevation( const std::string &root, const string_list elev_src,
     TG_LOG(SG_GENERAL, SG_DEBUG, "Average surface height of point list = " << average);
 
     return average;
-}
\ No newline at end of file
+}
diff --git a/src/Airports/GenAirports850/main.cxx b/src/Airports/GenAirports850/main.cxx
index fb89bb78..d10d0873 100644
--- a/src/Airports/GenAirports850/main.cxx
+++ b/src/Airports/GenAirports850/main.cxx
@@ -308,6 +308,17 @@ int main(int argc, char **argv)
         exit(-1);
     }
 
+    // try to figure out which apt.dat version we are reading and bail if version is unsupported
+    in >> skipeol;
+    char line[20];
+    in.getline(line, 20);
+    in.close();
+    int code = atoi(line);
+    if (code == 810) {
+      TG_LOG( SG_GENERAL, SG_ALERT, "ERROR: This version of genapts does not support version 810 apt.dat files." );
+      exit(-1);
+    }
+
     // Create the scheduler
     Scheduler* scheduler = new Scheduler(input_file, work_dir, elev_src);