What does 14 CFR 135.223 refer to?

The regulatory reference 14 CFR 135.223 pertains specifically to the requirements surrounding flight planning known as the 1/2/3 rule. This rule indicates that for certain operations, a flight must be planned to either allow for a destination and an alternate airport that can be reached within one hour’s flying time of the intended flight under normal cruising speed, or have the necessary fuel reserves for that duration.

Comprehending this regulation is essential for ensuring safety and compliance in flight operations, as it assists pilots and dispatchers in assessing viable flight paths and fuel management to mitigate risks associated with unforeseen circumstances like adverse weather or in-flight emergencies. Thus, the 1/2/3 rule is critical for effective and safe flight planning in Part 135 operations.

The other options, while related to aviation regulations, do not accurately reflect what 14 CFR 135.223 specifically addresses.