FAA Ground School Practice Test

What should be selected on the omnibearing selector (OBS) for a direct flight from Mercer County Regional Airport to Minot VORTAC?

1. 360*

2. 270*

3. 180*

4. 359*

The correct answer is: 359*

When planning a direct flight from Mercer County Regional Airport to Minot VORTAC, it's essential to understand how the omnibearing selector (OBS) works. The OBS provides orientation to navigate a VOR (VHF Omnidirectional Range) station, which helps determine the course to fly. In this case, the correct selection on the OBS should reflect the magnetic course to Minot VORTAC from your departure point. By selecting 359 degrees, you would be aligning with the radial that corresponds to the desired course for a direct flight toward Minot, located north of Mercer County. This choice ensures that when you track to the VORTAC, you remain on the correct course. Choosing a different value, such as 360, may seem similar but does not account for the slight adjustments required for wind correction or precise navigation. Selecting 270 would send you directly west, and 180 would direct you south, neither of which point toward your destination. Therefore, the option of 359 degrees provides the most accurate heading for the intended direct flight, considering navigational factors and relative positioning.