Final answer:
IFR fuel requirements for a commuter air operator using a multi-engine, propeller-driven aircraft involve enough fuel to reach the destination, potentially an alternate airport, and additional 45 minutes of flight at normal cruising speed. These regulations are part of the Federal Aviation Regulations to ensure flight safety.
Step-by-step explanation:
The question pertains to the fuel requirements for an Instrument Flight Rules (IFR) flight by a commuter air operator using a multi-engine, propeller-driven aircraft. According to the Federal Aviation Regulations (FARs), such aircraft must carry enough fuel to complete the flight to the first airport of intended landing and, assuming normal cruising speed, to fly after that for at least 45 minutes. However, for commuter operations under FAR Part 135, which typically applies, the requirements are slightly different: they must have sufficient fuel to fly to the first point of intended landing, then to the alternate airport if one is required, and then after that to fly for 45 minutes at normal cruising speed.
For IFR flights, if the weather forecasts for both the destination airport and any required alternate airports during the period from one hour before to one hour after the estimated time of arrival (ETA) are above certain minima, then no alternate airport is needed. If an alternate is required, the aircraft must carry enough fuel to proceed to the alternate airport and then fly for 45 minutes at normal cruising speed.
These rules ensure the safe completion of flights, accounting for unexpected conditions or delays. Pilots and operators must carefully plan their fuel policy considering these regulations to maintain adequate reserves for safety.