FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceEasy
A dispatcher is filing an IFR flight plan for a flight above 3,000 feet AGL on a magnetic course of 095°. Per 14 CFR 91.179, which cruising altitude should be assigned?
- A9,000 feet
- B8,000 feet
- C12,000 feet
- D10,000 feet
Show answer & explanationAnswer & explanation
Correct answer: A. 9,000 feet
Under the hemispheric cruising altitude rule, IFR flights on magnetic courses of 0°–179° use odd thousands of feet (9,000, 11,000, etc.), while courses of 180°–359° use even thousands. Since 095° falls in the 0°–179° range, 9,000 feet is correct.
Why the other options are wrong
- B. 8,000 is an even thousand, appropriate only for westbound (180°–359°) courses.
- C. 12,000 is also an even thousand, incorrect for this course direction.
- D. 10,000 is an even thousand, not valid for this course.
Hemispheric Cruising Altitude Rule
14 CFR 91.179 assigns IFR cruising altitudes based on magnetic course: odd thousands for 0°–179°, even thousands for 180°–359°.
- Applies above 3,000 ft AGL under IFR
- 0°–179° = odd thousands (e.g., 9,000, 11,000)
- 180°–359° = even thousands (e.g., 8,000, 10,000)
Memory trick: 'Odd East, Even West' — think of the sun rising odd in the East.