What is the maximum fuel range of the current aircraft under the specified conditions?

• A. 631 nm
• B. 500 nm
• C. 700 nm
• D. 900 nm

Answer: (A)

Maximizing the distance you can fly on the available fuel comes from flying at the most fuel‑efficient point — the combination of cruise speed and altitude that gives the lowest fuel burn per mile while still meeting all required reserves. Range is essentially cruise speed times endurance, and endurance equals usable fuel divided by the fuel burn rate. So the farthest you can go is achieved by using the fuel in the most economical way and then adding the mandated reserves and alternates.

Under the specified conditions, the usable fuel and the airplane’s fuel burn at the chosen efficient cruise yield an endurance that translates to 631 nautical miles of range. Distances much larger than that would require more fuel than is permitted by reserves, alternate fuel, or regulatory requirements, while smaller distances would not be taking full advantage of the efficient cruise mode.