Australia CASA Instrument Proficiency Practice Exam

The requirements for indicating lighting at an alternate aerodrome are specifically designed to ensure safety and operational efficiency under various conditions. The correct answer emphasizes that non-PAL (Pilot Activated Lighting) systems are adequate for use, provided that dual VHF radios are available in the aircraft. This is crucial because dual VHF radios provide redundancy; if one radio fails, the other can be used to activate the aerodrome lighting, ensuring that pilots can land safely at an alternate airport even in low-visibility or nighttime conditions.

The ability to activate these lighting systems enhances situational awareness and assists in approach and landing, which is particularly important in emergencies when diverting to an alternate aerodrome. Other choices do not meet the safety standards required for alternate aerodromes: daylight-only lighting does not account for night operations, traditional navigational aids alone do not ensure visibility of the aerodrome itself, and no lighting requirement in clear weather neglects the unpredictable nature of weather changes that can occur.