diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7b53884..ae40dfc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## v.1.4.1
 
-- Fix carsh by missing parameter
+- Fix crash by missing parameter
 
 ## v.1.4.0
 
diff --git a/nasal/aerotow.nas b/nasal/aerotow.nas
index cfcc97b..96e2e82 100644
--- a/nasal/aerotow.nas
+++ b/nasal/aerotow.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Aerotow object
+# Class Aerotow for enable and disable scenario with aerotow aircraft.
 #
 var Aerotow = {
     #
diff --git a/nasal/aircraft.nas b/nasal/aircraft.nas
index 1e62f93..6b92dfb 100644
--- a/nasal/aircraft.nas
+++ b/nasal/aircraft.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Parent object of Aircraft
+# Parent class of Aircraft
 #
 var Aircraft = {
     #
diff --git a/nasal/dialogs/route.nas b/nasal/dialogs/route.nas
index dcc5e42..7c243f3 100644
--- a/nasal/dialogs/route.nas
+++ b/nasal/dialogs/route.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Object for hande Route Dialog
+# Class for hande Route Dialog
 #
 var RouteDialog = {
     #
diff --git a/nasal/dialogs/thermal.nas b/nasal/dialogs/thermal.nas
index 8f8e9fc..5225b8b 100644
--- a/nasal/dialogs/thermal.nas
+++ b/nasal/dialogs/thermal.nas
@@ -9,6 +9,9 @@
 # under the GNU Public License v3 (GPLv3)
 #
 
+#
+# Class Thermal for handle add new thermal.
+#
 var Thermal = {
     #
     # Constructor
diff --git a/nasal/flight-plan.nas b/nasal/flight-plan.nas
index 1d4d352..01530b6 100644
--- a/nasal/flight-plan.nas
+++ b/nasal/flight-plan.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Flight Plan object
+# Class FlightPlan for crate and save as XML file the flight plan for AI scenario.
 #
 var FlightPlan = {
     #
@@ -93,7 +93,7 @@ var FlightPlan = {
             "lat"     : rwyResult.runway.lat,
             "lon"     : rwyResult.runway.lon,
             "heading" : rwyResult.runway.heading,
-        }
+        };
     },
 
     #
diff --git a/nasal/io/flight-plan-writer.nas b/nasal/io/flight-plan-writer.nas
index 7cd61b7..565df39 100644
--- a/nasal/io/flight-plan-writer.nas
+++ b/nasal/io/flight-plan-writer.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Object for write flight plan to the XML file
+# Class FlightPlanWriter for write flight plan to the XML file
 #
 var FlightPlanWriter = {
     #
diff --git a/nasal/message.nas b/nasal/message.nas
index c2316e5..b7de96c 100644
--- a/nasal/message.nas
+++ b/nasal/message.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Object for display messages
+# Class Message for display messages on the screen with read by speech synthesizer.
 #
 var Message = {
     #
diff --git a/nasal/scenario.nas b/nasal/scenario.nas
index 23b0146..1987b04 100644
--- a/nasal/scenario.nas
+++ b/nasal/scenario.nas
@@ -10,16 +10,16 @@
 #
 
 #
-# Scenario object
+# Class Scenario for create AI scenario XML file and attach it to scenario property list for load it.
 #
 var Scenario = {
     #
     # Constants
     #
-    SCENARIO_ID:         "aerotow_addon",
-    SCENARIO_NAME:       "Aerotow Add-on",
-    SCENARIO_DESC:       "This scenario starts the towing plane at the airport where the pilot with the glider is located. Use Ctrl-o to hook the plane.",
-    FILENAME_SCENARIO:   "aerotown-addon.xml",
+    SCENARIO_ID:       "aerotow_addon",
+    SCENARIO_NAME:     "Aerotow Add-on",
+    SCENARIO_DESC:     "This scenario starts the towing plane at the airport where the pilot with the glider is located. Use Ctrl-o to hook the plane.",
+    FILENAME_SCENARIO: "aerotown-addon.xml",
 
     #
     # Constructor
diff --git a/nasal/timer.nas b/nasal/timer.nas
index 673b314..d559024 100644
--- a/nasal/timer.nas
+++ b/nasal/timer.nas
@@ -10,7 +10,7 @@
 #
 
 #
-# Class Timer for wrapping maketimer()
+# Class Timer for wrapping maketimer() function.
 #
 var Timer = {
     #