The International Cessna^® 170 Association

There is a good article in this month's IFR Resfresher by Judy Cadmus. The articel discusses the benefits and possible costs associated with the WAAS upgrade to Garmin equipment. From the sound of it - I believe I would have to pay for more than just the Garmin upgrade due to where my unit is installed on the panel.

My question is this: Judy Cadmus suggests in her article that the WAAS upgrade is necessary to continue to use a currently IFR certified GARMIN for primary IFR enroute, "...other advantages include its use as a primary means of navigation for enroute IFR..." I have been under the impression the WAAS upgrade is optional not mandatory. My current IFR certified Garmin 430 is more than adequate for the kind of IFR I fly.

I believe the pertinent word is "primary". Your GPS is presently certified as a secondary source of navigation, not primary. You must have a VOR to legally navigate with it. (Don't ask how they can continue to insist on this when virtually all GPS navigation is off-route and not verifiable by VOR. But when they clear you to a point colocated/co-defined with a VOR, then you are not to rely solely upon the GPS to make that determination. You are supposedly using the GPS as an "additional" type of nav.)

Thanks for the clarification George.

Robert,

There's more information here http://www.avionicswest.com/myviewpoint/1500_waas.htm (in case you didn't see this on the other thread).

Best Regards,

John

Here is the update on the 430/530 WAAS units
http://www.garmin.com/manuals/GNS530W_W ... Series.pdf

I can't bring up that update, is it just a problem with my computer? where is the original thread? Jon

Both links work for me