I found this DME indicator on the Cessna 210. Its mode switch has four positions - NAV1, NAV2, RNAV and HOLD. NAV1 and 2 are clear - it uses the NAV1 and 2 freq respectively. I'm wondering what the other two do, especially HOLD ?

RNAV is also quite logical - it uses the position selected in the RNAV selector. But how does the DME indicator determine the distance/speed to the RNAV position ? By using the GPS ?


1 Answer 1


Once you select and tune NAV 1 or NAV 2 (assuming the NAV 1 or NAV 2 Navaid has associated DME) and then select the "Hold" mode the DME will stay on that frequency after you change the NAV 1 or NAV 2 to another frequency.

Note that the DME hold mode is only associated with NAV 1 and NAV 2.

The RNAV and GPS interface with the 400 DME unit would depend on integrated system compatibility/interoperability. It's a fairly old system.


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