At 18,000 ft and -41 °C with 2,500 RPM, what is the approximate flight time under VFR night fuel reserve conditions?

To determine the approximate flight time under VFR night fuel reserve conditions, it's important to consider several factors, including the fuel consumption rates at altitude and temperature, as well as the regulatory requirements for fuel reserves during night flying.

In this scenario, the fuel consumption is influenced by altitude and temperature, typically resulting in better performance and fuel efficiency because of thinner air. The RPM setting also plays a role, as a higher RPM could indicate a power setting that contributes to increased fuel consumption.

The calculation is based on the fuel flow rate that is established at the given altitude and conditions. For night VFR operations, regulations stipulate that an aircraft must carry sufficient fuel to fly to the first point of intended landing and then have an additional reserve of at least 45 minutes of fuel for cruising at the normal cruising speed.

When calculating the flight time, we consider that an aircraft's fuel consumption in those conditions allows for extended flight availability. The specific combination of factors leads to a total potential flight time that aligns most closely with 2 hours and 27 minutes. This choice reflects a balance of required reserve fuel and the aircraft's endurance capabilities under the given parameters.

Thus, while the other options present different time frames, they may not adequately satisfy the necessary reserve conditions