498
B. Arizmendi et al.
advantage of special properties of the materials or physical principles. Regarding
the special properties, super-hydrophobic materials are investigated for anti-icing
and de-icing purposes to decrease the adhesion of the impinging droplets on
aerodynamic surfaces [116]. In addition, graphite is studied as well due to its
high thermal inertia [117]. Furthermore, shape memory alloys change their shape
when energy is supplied to them, generally external heating. This property has
been exploited to crack a surface of ice in a similar manner as the de-icing boots
[117]. Electromagnetic forces have been investigated to induce sudden motions on
elements that hit the protected surface and detach the ice [118]. These forces are
investigated to modify the shape of a surface in a similar manner as the shape
memory form alloys [117]. Finally, ultrasounds are under investigation [119]. Sound
waves are used to create stress on the layer of ice and to detach it from the surface.
15.4.3 Regulations and Certification
The regulations related to ice accretion seek to ensure the safe and reliable
operation of aircraft equipped with ice protection systems when those are exposed
to atmospheric icing conditions. On another note, an ice envelope consists of a
combination of atmospheric parameters that describe an atmospheric icing scenario
such as LWC, MVD, and OAT and cloud length. Certification for aircraft effective
protection against icing effects is attained by ensuring the aircraft can fly safely
through a predetermined set of icing envelopes. Next the most relevant regulations
and certifications are presented.
15.4.3.1 FAA Code of Flight Regulations
The American Federal Aviation Administration (FAA) belongs to the U.S. department of transportation whose mission is to ensure fast, safe, reliable, and efficient
transport. Within the FAA, the Aviation Safety department (AVS) is in charge of
elaborating regulations for the certification of commercial and civil aircraft, namely
Code of Federal Regulation (CFR). The regulations for flight in icing conditions
can be found in the section 25 of the chapter 14 of the CFR. The Appendix C of
this section presents a range of icing envelopes that aircraft should be protected to,
which are divided into two:
• Continuous maximum icing: Set of icing envelopes which characterize long duration encounters found when aircraft fly through stratiform clouds. These clouds,
as presented in the Sect. 15.2.1.1, generally present low liquid water content
and largely extend in the horizontal direction. The values of the atmospheric
parameters can be found from the graphs depicted in Figs. 15.20 and 15.21, for a
reference cloud length of 17.4 nautical miles. In addition, on the regulation one
B. Arizmendi et al.
advantage of special properties of the materials or physical principles. Regarding
the special properties, super-hydrophobic materials are investigated for anti-icing
and de-icing purposes to decrease the adhesion of the impinging droplets on
aerodynamic surfaces [116]. In addition, graphite is studied as well due to its
high thermal inertia [117]. Furthermore, shape memory alloys change their shape
when energy is supplied to them, generally external heating. This property has
been exploited to crack a surface of ice in a similar manner as the de-icing boots
[117]. Electromagnetic forces have been investigated to induce sudden motions on
elements that hit the protected surface and detach the ice [118]. These forces are
investigated to modify the shape of a surface in a similar manner as the shape
memory form alloys [117]. Finally, ultrasounds are under investigation [119]. Sound
waves are used to create stress on the layer of ice and to detach it from the surface.
15.4.3 Regulations and Certification
The regulations related to ice accretion seek to ensure the safe and reliable
operation of aircraft equipped with ice protection systems when those are exposed
to atmospheric icing conditions. On another note, an ice envelope consists of a
combination of atmospheric parameters that describe an atmospheric icing scenario
such as LWC, MVD, and OAT and cloud length. Certification for aircraft effective
protection against icing effects is attained by ensuring the aircraft can fly safely
through a predetermined set of icing envelopes. Next the most relevant regulations
and certifications are presented.
15.4.3.1 FAA Code of Flight Regulations
The American Federal Aviation Administration (FAA) belongs to the U.S. department of transportation whose mission is to ensure fast, safe, reliable, and efficient
transport. Within the FAA, the Aviation Safety department (AVS) is in charge of
elaborating regulations for the certification of commercial and civil aircraft, namely
Code of Federal Regulation (CFR). The regulations for flight in icing conditions
can be found in the section 25 of the chapter 14 of the CFR. The Appendix C of
this section presents a range of icing envelopes that aircraft should be protected to,
which are divided into two:
• Continuous maximum icing: Set of icing envelopes which characterize long duration encounters found when aircraft fly through stratiform clouds. These clouds,
as presented in the Sect. 15.2.1.1, generally present low liquid water content
and largely extend in the horizontal direction. The values of the atmospheric
parameters can be found from the graphs depicted in Figs. 15.20 and 15.21, for a
reference cloud length of 17.4 nautical miles. In addition, on the regulation one