diff --git a/aerodynamic_analysis/src/taw/tawCalculatePolarConfig.h b/aerodynamic_analysis/src/taw/tawCalculatePolarConfig.h
index 8f60d2424782d0ecd614214b82a17012811df75f..5560d23857e7978f12db7e9dc7bf48fefe86849e 100644
--- a/aerodynamic_analysis/src/taw/tawCalculatePolarConfig.h
+++ b/aerodynamic_analysis/src/taw/tawCalculatePolarConfig.h
@@ -123,9 +123,9 @@ class tawCalculatePolarConfig{
 
     /* High lift calibration data */
     struct hl_polar_calibration_values {
-        double CL_max;          /**< maximum CL value which should be reached */
-        double delta_CD;        /**< Constant delta for drag calibration */
-        double factor_CD;       /**< Factor for drag calibration */
+        double CL_max = NAN;          /**< maximum CL value which should be reached */
+        double delta_CD = NAN;        /**< Constant delta for drag calibration */
+        double factor_CD = NAN;       /**< Factor for drag calibration */
     };
     std::unordered_map<std::string, hl_polar_calibration_values> hl_polar_calibration_data; /**< Container for storing all high lift polar calibration and correction values */