PA46 with radar?
My understanding is both ATC and ADSB/XM use a similar product for radar, and IMO the lag time is a big problem when it comes to close range navigation near imbedded stuff, and convective activity in general where 5 minutes can be a lifetime.
We have NEXRAD onboard as well, it's great for keeping a eye on the big picture, however going IMC without real radar in those conditions
YMMV
Well, my mileage definitely varies. I've never flown with radar but have had Nexrad data since before the beginning, i.e. on Cheap Bastard running on an RF Palm device. Cockpit Nexrad is a game changer for everyone, particularly those without access to onboard radar.
First, I don't really know how ATC and ADSB/XM products are similar but it is pretty clear to me that ATC has no time delay. Agreed?
ADSB certainly does have a time delay. It's not a big deal as long as it's accounted for.
Jesse did a good job of describing how Nexrad imagery can be used in thunderstorm studded skies. Here's my take.
I decided some years ago while flying IFR in IMC conditions that penetrating clouds that contain convective storms is not something I will be doing any longer. I've flown into IMC with embedded storms and scared the crap out of myself. I've battled a few (very few) convective storms without AP or any information other than that provided by ATC. I don't do that any longer.
What I will do is fly cross country on stormy afternoons with an AP, Nexrad and as much ATC help as I can get. I stay visual 90%+ of the time. Let me say that again, I stay in visual contact with enough of the external environment to hand fly the airplane 90%+ of the time. I only penetrate clouds where and when I know where I will exit same cloud - and mainly do it for expediency because it's on my course. Otherwise I stay out of solid IMC conditions. I stay out of convective storms. I may get wet, I met get tossed a bit but I stay visual.
Obviously I fly on an IFR plan and clearance. That makes the cloud penetration legal. More important it keeps the lack of VFR cloud clearances legal. Much of my flying is right up against clouds... sometimes storm clouds. Flying on an IFR clearance is the best way to do this kind of flying with few exceptions. Whether VFR and IFR, ATC's help is always sought and welcome. They have good information and even better experience. Stupid to do otherwise.
I rarely make loggable IFR approaches in these conditions. Most approaches are visual because the conditions are visual. IFR approaches are for low ceilings and generally stable conditions.
This is a flight I made today:
http://flightaware.com/live/flight/N215TG/history/20150806/1900Z/KSSI/8NC8
I was pretty confident it could be completed as planned but my passenger and I were more than well prepared to land somewhere else and wait things out. We didn't have to. It was a fun and interesting flight.
Twice during this flight I saw the effect of Nexrad delays. In one case I saw a strong, fresh buildup with rain about 3 minutes before there was any indication on my ADSB Nexrad display. But I was visual at 9,000' so this counts as 'calibration of Nexrad with my mark 20 eyeballs'. That is, no problem.
In the other case I asked for a right turn to direct final destination when about 30 miles out and 5,000'. I was skimming just below cloud base. RDU approach was very busy at that point and responded with, "turn left 20 degrees for weather" (!!) While I could see along my final course with just a bit of haze, I couldn't see the sudden buildup forming overhead, above cloud base, between me and my final destination. Within a minute or two, the Nexrad imagery filled in as the first strokes of lightening marked by previously requested course. These storms were forming quickly and the Nexrad update time was a real factor but manageable because I was visual and getting help from ATC. When I cleared the line of clouds overhead I requested direct, got it, then canceled IFR for the final 15 miles or so.
Few people talk about what Nexrad does better than anything else and that's seeing around corners. Like Superman! No attenuation, no elevation or azimuth adjustment, just a complete, slightly aged picture. When Nexrad was still new in the cockpit it was fun being able to complete flights when the radar equipped jets were stuck. It wasn't long before G396s seemed to be in everyone's cockpit but for a few months, maybe a year, it was very 'interesting' out there buzzing around with the G396. And Cheap Bastard was just plain 'magic' when it was the only game in town.
My experience is primarily in the SE US. I've flown conditions across the country and know things are different....I don't necessarily know exactly what's different but things are different. Nevada cloudbases at 18,000 feet or above are completely different. Texas storms along the 'dew line' or whatever are different. Giant midwest hail spewing green monsters are different. But Nexrad makes a lot of things possible and safe for light planes that simply weren't in the past.
Debate is fine with old school naysayers but if I'm flying a light plane cross country with Nexrad as my primary storm avoidance tool, I'd say get some experience with it, learn to use it and find out just how effective it can be in getting you where you want to be safely.
Did I say anything about penetrating a line of storms? The stuff in bold is exactly what I'm talking about. You can look 200 miles ahead and see a cluster of storms and choose a route that will take you well clear of it many times. I do this all the time and I have onboard radar. I still use the XM weather to decide far in advance how to steer clear. Of course you don't use the nexrad data for penetrating storms.
