XM Weather vrs On board radar

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    Hi I am a new member and am in the process of purchasing a 340. My existing aircraft (Piper Cherokee Lance) has XM weather, I love it and would install it in any new aircraft I acquire if it is not already equipped. I see that a lot of the 340 fleet seems to be equipped with Bendix 160 Radar. How good is this radar? While I know all about the lag issues with Satellite weather, to those pilots that have both, Radar and XM, how much do you continue to use the onboard radar? Do you find that you accumulate enough skill and trust in the onboard radar that you feel comfortable relying on it when it is conveying different information than the satellite weather?


    The 160 is a fair radar, I operated one for 2 years and it was a good performer. I spent money keeping it operational due it’s age. You can’t go past a GWX68 or 70, they are far superior.

    XM is great for planning but dodging around weather can’t be done in IMC without a good radar. XM is not for tactical avoidance.



    XM and on-board tell you different things. XM is nice because it will tell you what’s out well beyond what you can see. So for example, if I see that right in front of me is a bunch of storms, with XM I can see whether left or right is a better way to go. It has a delay with it. So strategic decision.

    On-board tells you what the real weather is doing right now in front of you. It’s good for tactical decisions, like “10 left now” to thread the needle through storms. I’ve used on-board radar to get through holes that felt about the size of my wingspan, but they were still holes. Since it’s right now, it’s good for storms.

    Radars are expensive and can be finicky. I’ve never had reliability issues with them, but many have. I installed a legacy unit (KWX56) in the 310 because I am satisfied with that performance at a cost that is more affordable for us, especially when we did the install.

    I’ve had good luck with 160s. If all else were equal, I’d rather have a newer one. But all else is never equal.


    As Ted says, XM is situational, onboard is tactical. Use both. I had the RDR 160, XM, and WSI in our Aztec. I set the XM in animation mode on a 696, the WSI and the RDR 160 displayed on an Avidyne ex600. Once I was into the “green” the RDR 160 came on to keep me out of any yellow, the XM gave me cell movement trends to keep me aware of the general direction of my “outs” and the RDR 160 backed up that information plus added real time information as to timing my decisions.


    Thanks for the responses, that was helpful and just the kind of information that I was looking for.



    The value of on board radar also changes based on where you fly. It has never seemed that essential on the west coast – but I would think in the midwest and southeast it would be critical.

    Another caution is even if you are equipped with on board radar, unless you are experienced in using it you can set yourself up for trouble.

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