For IFR aircraft operating at FL290 and above in non-RVSM airspace, what is the altitude interval for aircraft flying from 0-179 degrees?

For aircraft operating under Instrument Flight Rules (IFR) at Flight Level 290 (FL290) and above in non-Reduced Vertical Separation Minimum (RVSM) airspace, the altitude assignment is determined by the magnetic azimuth (direction) in which the aircraft is flying.

In this context, aircraft flying compass headings from 0 to 179 degrees are assigned altitudes in a specific manner to maintain safe vertical separation from other aircraft. The correct altitude interval for this group is any 4,000-foot interval starting at FL290. This is designed to provide adequate separation, as non-RVSM airspace does not allow for the same closer spacing that RVSM airspace does, which typically utilizes 1,000-foot separations.

The altitude assignments in non-RVSM airspace are structured to reduce the potential for turbulence and wake turbulence encounters by ensuring that aircraft flying in the same direction are spaced appropriately. Therefore, the interval of 4,000 feet provides the necessary vertical distance between aircraft for safety.

As you consider other options, they do not align with the established standards for altitudes in non-RVSM airspace. Odd or even intervals alone do not provide the necessary details for correct altitude assignments needed to ensure safe operations