Which rule determines flight levels based on magnetic track?

Which rule determines flight levels based on magnetic track?

• A. QNH rule
• B. Semicircular rule
• C. VMC rule
• D. FMS rule

Answer: (B)

Flight levels are the altitude reference used above the transition altitude with the standard pressure setting. The semicircular rule assigns these levels according to magnetic track to keep opposite-direction traffic separated on the same routes. Specifically, if the magnetic course is 0° to 179° (eastbound), aircraft use odd flight levels; if the course is 180° to 359° (westbound), they use even flight levels. This arrangement helps prevent two aircraft on the same airway but traveling in opposite directions from occupying the same level. The other options relate to altimeter settings or are not the method used to determine flight levels.

Flight levels are the altitude reference used above the transition altitude with the standard pressure setting. The semicircular rule assigns these levels according to magnetic track to keep opposite-direction traffic separated on the same routes. Specifically, if the magnetic course is 0° to 179° (eastbound), aircraft use odd flight levels; if the course is 180° to 359° (westbound), they use even flight levels. This arrangement helps prevent two aircraft on the same airway but traveling in opposite directions from occupying the same level. The other options relate to altimeter settings or are not the method used to determine flight levels.