Is it permissible to operate the APU during fluid de-icing or anti-icing procedures?

The operation of the Auxiliary Power Unit (APU) during fluid de-icing or anti-icing procedures is not permissible due to safety and operational concerns. The APU produces heat and exhaust gases, which can interfere with the effectiveness of de-icing fluids and potentially lead to a dangerous situation. De-icing and anti-icing fluids are designed to remain on the surface of the aircraft, creating a protective layer against ice and frost. Running the APU could cause the exhaust to disrupt this protective layer, which may leave the aircraft vulnerable to ice formation.

Additionally, there are strict regulations and best practices in aviation that ensure the safety of aircraft operations during these critical procedures. Maintaining clear and intact surfaces is essential for the safety of the flight. Thus, operating the APU while de-icing or anti-icing is not allowed to avoid compromising the effectiveness of the fluids used in these processes.