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:

VHF navigation, particularly localizer and localizer back course approaches, remains important despite GPS, but is a common source of confusion for pilots.
The article first reviews VOR basics, explaining how an Omni-Bearing Selector (OBS) combines with a received radial to provide "To/From" indications and course deviation.
Localizers, however, transmit a static beam where OBS is irrelevant; pilots must understand "front course" and "back course" to correctly interpret the Course Deviation Indicator (CDI).
Correctly flying localizer approaches requires pilots to adapt their mental response to the CDI (chase or correct away from the needle) based on whether they are inbound/outbound on the front/back course, a critical skill often misunderstood as "reverse sensing."

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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.