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Why have Dual screen NAV/COM/GPSs?

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General Aviation

I am just starting IFR training and planning to update the radios in an IFR certified Cessna 172N.  I've seen several panels where dual NAV/COM/GPSs have been installed with two screens eg a Garmin 430 and a 530. Why?  What would be lost by installing a Garmin 530 with a screen, and something like a Garmin SL30 without a screen?

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1 Answers



  1. John D. Collins on Nov 14, 2012

    Backup for the GPS. Use one GPS for navigation and the other for a different function, for example if you have a traffic system.

    Most aircraft have dual Nav and dual Com radios. They are not required, but if one fails in flight, you can still conduct the flight with a minimum loss of capability.

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