For an IFR flight on a course of 150 degrees, which altitude assignment is correct?

For an IFR flight on a course of 150 degrees, which altitude assignment is correct?

• A. Even altitude
• B. Flight level based on course
• C. Odd altitude
• D. MEAs

Answer: (C)

On IFR routes, altitude blocks are assigned by direction to keep eastbound and westbound flights in different layers. For low-altitude routes using federal airways, eastbound flights (course 000–179 degrees) fly an odd number of thousands plus 500 feet (3,500; 5,500; 7,500, etc.), while westbound flights (course 180–359 degrees) use even thousands plus 500 feet (4,500; 6,500; 8,500, etc.). A course of 150 degrees is eastbound, so you would select an odd altitude. Flight levels are a different framework for high-altitude operations, and minimum enroute altitude (MEA) is about obstacle clearance, not the direction-based assignment itself. So the correct concept is using an odd altitude.

On IFR routes, altitude blocks are assigned by direction to keep eastbound and westbound flights in different layers. For low-altitude routes using federal airways, eastbound flights (course 000–179 degrees) fly an odd number of thousands plus 500 feet (3,500; 5,500; 7,500, etc.), while westbound flights (course 180–359 degrees) use even thousands plus 500 feet (4,500; 6,500; 8,500, etc.). A course of 150 degrees is eastbound, so you would select an odd altitude. Flight levels are a different framework for high-altitude operations, and minimum enroute altitude (MEA) is about obstacle clearance, not the direction-based assignment itself. So the correct concept is using an odd altitude.