Final answer:
Alternate airport fuel requirements involve the additional fuel necessary for aircraft to divert to a different landing location, considering factors like additional travel distance and reserve fuel. The shift towards alternative fuels is crucial due to dwindling sources of petroleum and environmental impacts. The US Department of Energy highlights efforts in exploring options such as algal fuel for military and aviation uses.
Step-by-step explanation:
The alternate airport fuel requirements pertain to the provisions needed for aircraft when planning for a different landing location than originally intended, which might be necessitated by unforeseen circumstances such as weather, emergencies, or airspace restrictions. These requirements take into account the additional fuel needed to reach the alternate airport, hold for a period of time, and serve as a contingency to ensure safe operation of an aircraft. In the context of alternative fuels, the exploration of other sources is crucial due to the decreasing petroleum supply and the environmental impact of traditional fossil fuels.
According to the US Department of Energy, alternative fuels such as algal fuel are being explored to address these concerns. However, the adoption of alternative fuels in aviation is complex due to factors like the energy transfer rate during refueling and the variance in energy density compared to conventional fuels. The military has also shown interest in these developments, as indicated by renewable fuels being tested in Navy ships and aircraft.