diff --git a/OpenSky.Agent/Views/Models/AircraftTypesViewModel.cs b/OpenSky.Agent/Views/Models/AircraftTypesViewModel.cs
index ffa4f07..76c605c 100644
--- a/OpenSky.Agent/Views/Models/AircraftTypesViewModel.cs
+++ b/OpenSky.Agent/Views/Models/AircraftTypesViewModel.cs
@@ -204,7 +204,7 @@ public class AircraftTypesViewModel : ViewModel
         /// The override fuel type.
         /// </summary>
         /// -------------------------------------------------------------------------------------------------
-        private FuelType overrideFuelType;
+        private FuelType overrideFuelType = FuelType.NotUsed;
 
         /// -------------------------------------------------------------------------------------------------
         /// <summary>
@@ -1215,7 +1215,7 @@ private void AddAircraftType()
                 IsGearRetractable = this.Simulator.AircraftIdentity.GearRetractable,
                 Name = this.Name,
                 VersionNumber = this.VersionNumber,
-                ManufacturerID = this.SelectedManufacturer.Id,
+                ManufacturerID = this.SelectedManufacturer?.Id,
                 Category = this.Category,
                 IsVanilla = this.IsVanilla,
                 IncludeInWorldPopulation = this.IncludeInWorldPopulation,
@@ -1321,6 +1321,7 @@ private void CancelAddAircraft()
             this.MaximumPrice = 0;
             this.MinimumRunwayLength = 0;
             this.Comments = null;
+            this.OverrideFuelType = FuelType.NotUsed;
 
             this.aircraftTypeBeingUpdated = null;
         }
diff --git a/changelog.txt b/changelog.txt
index 3036b19..25a27cd 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -7,6 +7,8 @@ Version 0.5.3 (ALPHA5)
 --------------------------------------------------------------------------------------
 - Improved aircraft type updates, next version and variants updated automatically
   in improved API method
+- Changed default fuel type override to NOT USED
+- Fixed crash if no manufacturer was selected
 
 --------------------------------------------------------------------------------------
 Version 0.5.2 (ALPHA5)