Reverse Sensing

Some of you are already yawning, thinking to yourselves, With GPS and moving maps, who needs VHF nav anyway? To an extent, thats a valid argument, especially regarding VORs. But, there are still a lot of localizer and localizer back course approaches out there, and you may have to fly one. You shouldnt entirely dismiss VHF navigation just yet.

Frank Bowlin

Tuesday, May 10, 2016 at 12:00 AM ET

Verified

Key Takeaways:

Despite GPS, VHF navigation, especially localizer approaches, remains a critical skill for pilots to master.
The article reviews VOR basics, explaining how the Omni-Bearing Selector (OBS), "To/From" indications, and Course Deviation Indicator (CDI) work together to guide navigation.
Localizers differ significantly from VORs, lacking OBS and "To/From" indications, which requires pilots to correctly interpret CDI movement—often involving a concept akin to "reverse sensing"—based on whether they are flying inbound/outbound on the front/back course.
Understanding when to "chase" or "correct away" from the CDI is crucial for flying localizer approaches accurately, a challenge that can be simplified with an HSI.

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Some of you are already yawning, thinking to yourselves, “With GPS and moving maps, who needs VHF nav anyway?” To an extent, that’s a valid argument, especially regarding VORs. But, there are still a lot of localizer and localizer back course approaches out there, and you may have to fly one. You shouldn’t entirely dismiss VHF navigation just yet.

Look at the Grand Forks LOC BC Runway 17R approach. If you know right away how to set up your navigation, what OBS settings to use and how to read your instruments (HSI or VOR/LOC indicator) on the approach with procedure turn and missed, you can stop here and even skip next month’s clinic.