When no alternate is required for turbojet aircraft in IFR, what is the minimum fuel requirement?

For turbojet aircraft operating under Instrument Flight Rules (IFR), when no alternate airport is required, the minimum fuel requirement is specified as 30 minutes of fuel at cruise speed. This regulation is designed to ensure that the aircraft has sufficient fuel reserves to handle unexpected situations such as delays or changes in flight planning that may occur on approach or after reaching the destination.

Having a 30-minute fuel reserve provides a safety margin to account for variations in actual flight conditions or unforeseen circumstances that might require an extension of the flight time. This regulation is part of ensuring that pilots maintain a high level of safety and preparedness during IFR flights, which is particularly important given the high speeds and altitudes at which turbojet aircraft operate.

The other options reflect different time parameters that are not applicable in this specific situation regarding turbojet aircraft when no alternate is designated. Understanding the reasoning behind the 30-minute requirement emphasizes the importance of fuel management in ensuring safety and compliance within the operational framework of IFR flying.