Method of determining operating conditions of an exterior aircraft light comprising at least one light source , wherein the method includes: operating the at least one light source of the exterior aircraft light ; repeatedly detecting light with a light detector , which is located at the exterior aircraft light and configured for providing light detection values (I); characterized in that the method further includes: determining a smallest light detection value (I min ) provided by the light detector within a first period of time, and storing said smallest light detection value (I min ) as an element of a series of smallest light detection values (I min ); and in that the method further includes at least one of the following: determining a change of the elements of the series of smallest light detection values (I min ) over a second period of time, which is larger than the first period of time, and detecting erosion of an optical component , in particular a cover, of the exterior aircraft light based on the determined change of the elements of the series of smallest light detection values (I min ) over the second period of time; and determining, based on the series of smallest light detection values (I min ), an expectation value (I exp ) for the light detection value (I), individually comparing the detected light detection values (I) with said expectation value (I exp ), and detecting the presence of ambient light if at least one of the detected light detection values (I) exceeds the expectation value (I exp ) by more than a predetermined ambient light detection threshold. operating the at least one light source of the exterior aircraft light ; repeatedly detecting light with a light detector , which is located at the exterior aircraft light and configured for providing light detection values (I); characterized in that the method further includes: determining a smallest light detection value (I min ) provided by the light detector within a first period of time, and storing said smallest light detection value (I min ) as an element of a series of smallest light detection values (I min ); and in that the method further includes at least one of the following: determining a change of the elements of the series of smallest light detection values (I min ) over a second period of time, which is larger than the first period of time, and detecting erosion of an optical component , in particular a cover, of the exterior aircraft light based on the determined change of the elements of the series of smallest light detection values (I min ) over the second period of time; and determining, based on the series of smallest light detection values (I min ), an expectation value (I exp ) for the light detection value (I), individually comparing the detected light detection values (I) with said expectation value (I exp ), and detecting the presence of ambient light if at least one of the detected light detection values (I) exceeds the expectation value (I exp ) by more than a predetermined ambient light detection threshold. determining a change of the elements of the series of smallest light detection values (I min ) over a second period of time, which is larger than the first period of time, and detecting erosion of an optical component , in particular a cover, of the exterior aircraft light based on the determined change of the elements of the series of smallest light detection values (I min ) over the second period of time; and determining, based on the series of smallest light detection values (I min ), an expectation value (I exp ) for the light detection value (I), individually comparing the detected light detection values (I) with said expectation value (I exp ), and detecting the presence of ambient light if at least one of the detected light detection values (I) exceeds the expectation value (I exp ) by more than a predetermined ambient light detection threshold. <EOS>