Why is it critical to perform a visual inspection after de-icing?

Performing a visual inspection after de-icing is critical primarily to confirm that all critical surfaces of the aircraft are free of ice and snow. This step is essential for maintaining safety and ensuring that the aircraft can operate effectively. Ice and snow on critical surfaces, such as the wings, tail, and control surfaces, can significantly impair the aircraft's aerodynamic performance. These surfaces need to be free of contaminants to ensure optimal lift and control during takeoff and flight.

Visual inspections also help identify any areas where de-icing fluid may not have effectively removed the ice or where ice may have reformed. This step ensures that any issues can be addressed before the aircraft departs, thereby enhancing the safety of the flight. While checking fuel levels, maintenance issues, and passenger comfort are important aspects of overall aircraft operation, they do not directly relate to the critical need for de-icing and maintaining safe flight conditions, which is the primary focus of the visual inspection in this scenario.