100.“Air signals”, as defined in subsection (2) of this section, are of great importance for the guidance of aircraft. A false or inaccurate signal may cause loss of life, and this is reflected in the maximum penalty of life imprisonment for an offence under this section. It is an offence for service personnel:
to give a false air signal intentionally, or
to intentionally interfere with an air signal or with equipment used for making air signals.
101.A defence of lawful excuse would apply, for example, where a member of the armed forces has authority to correct an air signal or to adjust air signalling equipment.