Which statement about jet route altitude ranges is true?

Which statement about jet route altitude ranges is true?

• A. They start at 18,000 MSL and go to FL450
• B. They start at 10,000 MSL and go to FL180
• C. They start at 20,000 MSL and go to FL600
• D. They start at 0 MSL and go to FL200

Answer: (A)

Jet routes are the high‑altitude IFR en route airways used for long‑distance jet travel. In the United States, these routes are published for the airspace above 18,000 feet MSL up to flight level 450. The floor at 18,000 MSL aligns with the needs of high‑speed, high‑altitude traffic and radar capability, while the ceiling at FL450 reflects ATC and navigation constraints at the upper end of standard jet operations. Therefore, the true statement is that jet routes start at 18,000 MSL and go to FL450. The other ranges either begin below the jet route floor or end above the jet route ceiling or start from the surface, which isn’t applicable to jet routes.

Jet routes are the high‑altitude IFR en route airways used for long‑distance jet travel. In the United States, these routes are published for the airspace above 18,000 feet MSL up to flight level 450. The floor at 18,000 MSL aligns with the needs of high‑speed, high‑altitude traffic and radar capability, while the ceiling at FL450 reflects ATC and navigation constraints at the upper end of standard jet operations. Therefore, the true statement is that jet routes start at 18,000 MSL and go to FL450. The other ranges either begin below the jet route floor or end above the jet route ceiling or start from the surface, which isn’t applicable to jet routes.