### 11.1 [PERSON] ()
The use of passive IPSs becomes essential during takeoff operations since, according to the Federal Aviation Administration regulation, active IPSs cannot be switched on until the aircraft reaches 400 feet above the takeoff surface to avoid engine thrust reduction [12]. IWT tests performed at the takeoff and first climb conditions [13] on a nacelle lip-skin at T = \(-5~{}^{\circ}\)C and \(-12~{}^{\circ}\)C, v = 70 and 95 m/s, at an altitude of 3000 m, with a median volumetric diameter (MVD) equal to 20 \(\upmu\)m and liquid water content (LWC) equal to 0.3 and 1 g/m\({}^{3}\), demonstrated that the application of a superhydrophobic coating with active IPS switched off reduces the ice thickness, up to \(-49\%\), and the ice accreted impingement length up to \(-10\%\). At a higher LWC, i.e., 1 g/m\({}^{3}\), a reduced length and number of ice rivulets have also been observed for coated configurations [14]. A fundamental parameter to know about a coatings' performance in icing flight conditions is the ice adhesion strength on the aircraft surfaces. The lack of a standard for the ice adhesion measurements offers many opportunities and opens new routes in this area. The effects of ice types, test parameters, and surface properties on the measurement data of ice adhesion centrifuge tests have been studied elsewhere [15]. Surfaces with low ice adhesion strength, achieved through the application of coatings [16] or through laser texturing [17], might also be highly useful in facilitating or assisting the manual de-icing process performed by the crew members [18]. Technological solutions found for the aeronautical applications can be transferred in diverse domains, since ice accretion poses serious problems not only in the aviation industry, but also for dams and locks, express trains, air conditioners, refrigerators, wind turbines, solar panels, power lines, suspension bridges, heat pumps, and offshore oil platforms [19]. For instance, one of the problems involving the use of photovoltaic technology to produce renewable energy is that photovoltaic panels are subject to a significant loss of efficiency due to the accumulation of dust and dirt and, during the winter season, of snow and ice, which reduce or stop the energy production. The application of transparent coatings with superhydrophobic self-cleaning and icephobic properties might be proposed as valuable solution [20]. The results demonstrated that the ice adhesion of photovoltaic panels decreased by 69%, and the freezing delay time increased 17-fold compared with those of the unmodified surface. Jointly, the contact angle hysteresis and roll-off angle of coated surfaces were significantly reduced, and transparency, which is a key requirement for photovoltaic applications, was preserved. Although their application on vehicles' surfaces is still challenging, the development of hybrid IPSs offers new perspectives in the field of aviation, paving the way for more sustainable and efficient solutions for flight safety. Thanks to all the authors and peer reviewers for their valuable contributions to the Special Issue \"Superhydrophobic and Icephobic Coatings as Passive Ice Protection Systems for Aeronautical Applications\". The author declares no conflicts of interest.