Narrative:

Got WX for ZZZ1 to P19; IFR en route; thunderstorms north of our route of flight. Clear at destination. Reported clear passing cold front. Flying a G1000 C182 with onboard xm WX. Had I been flying a typical C182; I would not have gone. Looking back; poor adm and over reliance on technology onboard. Even though a yr has passed; thought it wise to report to ASRS as GA is still learning about technically advanced aircraft (taa). Decided to go because of onboard xm WX and ability to keep an eye on the thunderstorms north of our route. Flying in actual conditions in and out of clouds at 11000 ft (MEA 10000 ft); xm showed rain north of our route of flight as forecast; OAT 4 degrees C; otherwise clear of rain on our route. Entered a cloud and 30 seconds later heard rain on the windshield; looked up to see the entire windshield was white with ice; looked at the strut and ice was building quickly. Established it was vld icing. Immediately started a 180 degree right turn to depart the area; albuquerque was busy on the radio at the time; but deviated immediately to start turn. Approximately 1/2 way through turn managed to contact abq and advise of our situation; they cleared me down to 10000 ft. Noted OAT had dropped from 4 degrees C just 2-3 mins earlier to -7 degrees C. Completed the 180 degree turn and exited icing conditions 5 seconds later. Exited the cloud 20-30 seconds later with 1 inch of ice on wheel pant and strut with windshield totally covered. Advised abq that we were turning wswbound towards visible sunlight and descending to warmer temperatures in VFR conditions; canceled IFR and requested VFR flight following. Turned defrost on high; sunlight on window; was able to see out lower portion of front window in a few mins. About 2 mins later xm updated to show 30 mi of mixed snow and ice; now behind me. Ice melted completed over next 20-30 mins. Used G1000 terrain mapping and continuous s-turns to maintain situational awareness regarding terrain. Flew through mountain pass that was completely VFR towards area 20 NM north of tucson; handed off to tucson approach; then back to albuquerque as I turned north up I-10 towards chandler. Remainder of flight under VFR with no issue. I have prided myself on good adm; having flown since 1986; even though I only have 600 hours and about 75 hours of IFR at the time of this flight. However; I allowed having xm WX onboard to convince myself that I had enough data to conduct the flight. However; due to 5-10 min delay in rapidly changing WX; the xm data was not current enough and is no substitute for radar; which I did not have onboard this aircraft. My switch back to good positive adm was to immediately deviate from my clearance and start the 180 degree turn as soon as I encountered icing conditions. With the updated xm WX; a few mins too late; showing mixed snow and ice along my route; we would never have survived had we taken the 'we can fly through this' approach. Had I allowed the clear screen to convince me that I would fly through a small cell quickly; we would have been 2 mins into the snow and ice before the xm updated with the 4 mi to return; or 20-30 mi or more to fly through. I don't believe the C182 would have stayed airborne for either of these options at the rate the ice was building. I am now a CFI and soon to be a cfii and will be passing this story onto my students; especially those flying xm WX equipped aircraft. It is a great tool to look at WX; but it is not real time and does come with the risk of over dependence on the technology. My none-G1000 decision would have been to stay in a hotel in el paso; that decision should have carried over into the taa G-1000 C182.

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Original NASA ASRS Text

Title: A C182 WITH A G1000 NAV SYSTEM ENTERED ICING AT 11;000' IFR. A DELAYED XM RADAR UPDATE LATER DEPICTED THE WX. ACFT TURNED AND DSNDED OUT OF ICE CANCELING IFR.

Narrative: GOT WX FOR ZZZ1 TO P19; IFR ENRTE; TSTMS N OF OUR RTE OF FLT. CLR AT DEST. RPTED CLR PASSING COLD FRONT. FLYING A G1000 C182 WITH ONBOARD XM WX. HAD I BEEN FLYING A TYPICAL C182; I WOULD NOT HAVE GONE. LOOKING BACK; POOR ADM AND OVER RELIANCE ON TECHNOLOGY ONBOARD. EVEN THOUGH A YR HAS PASSED; THOUGHT IT WISE TO RPT TO ASRS AS GA IS STILL LEARNING ABOUT TECHNICALLY ADVANCED ACFT (TAA). DECIDED TO GO BECAUSE OF ONBOARD XM WX AND ABILITY TO KEEP AN EYE ON THE TSTMS N OF OUR RTE. FLYING IN ACTUAL CONDITIONS IN AND OUT OF CLOUDS AT 11000 FT (MEA 10000 FT); XM SHOWED RAIN N OF OUR RTE OF FLT AS FORECAST; OAT 4 DEGS C; OTHERWISE CLR OF RAIN ON OUR RTE. ENTERED A CLOUD AND 30 SECONDS LATER HEARD RAIN ON THE WINDSHIELD; LOOKED UP TO SEE THE ENTIRE WINDSHIELD WAS WHITE WITH ICE; LOOKED AT THE STRUT AND ICE WAS BUILDING QUICKLY. ESTABLISHED IT WAS VLD ICING. IMMEDIATELY STARTED A 180 DEG R TURN TO DEPART THE AREA; ALBUQUERQUE WAS BUSY ON THE RADIO AT THE TIME; BUT DEVIATED IMMEDIATELY TO START TURN. APPROX 1/2 WAY THROUGH TURN MANAGED TO CONTACT ABQ AND ADVISE OF OUR SITUATION; THEY CLRED ME DOWN TO 10000 FT. NOTED OAT HAD DROPPED FROM 4 DEGS C JUST 2-3 MINS EARLIER TO -7 DEGS C. COMPLETED THE 180 DEG TURN AND EXITED ICING CONDITIONS 5 SECONDS LATER. EXITED THE CLOUD 20-30 SECONDS LATER WITH 1 INCH OF ICE ON WHEEL PANT AND STRUT WITH WINDSHIELD TOTALLY COVERED. ADVISED ABQ THAT WE WERE TURNING WSWBOUND TOWARDS VISIBLE SUNLIGHT AND DSNDING TO WARMER TEMPS IN VFR CONDITIONS; CANCELED IFR AND REQUESTED VFR FLT FOLLOWING. TURNED DEFROST ON HIGH; SUNLIGHT ON WINDOW; WAS ABLE TO SEE OUT LOWER PORTION OF FRONT WINDOW IN A FEW MINS. ABOUT 2 MINS LATER XM UPDATED TO SHOW 30 MI OF MIXED SNOW AND ICE; NOW BEHIND ME. ICE MELTED COMPLETED OVER NEXT 20-30 MINS. USED G1000 TERRAIN MAPPING AND CONTINUOUS S-TURNS TO MAINTAIN SITUATIONAL AWARENESS REGARDING TERRAIN. FLEW THROUGH MOUNTAIN PASS THAT WAS COMPLETELY VFR TOWARDS AREA 20 NM N OF TUCSON; HANDED OFF TO TUCSON APCH; THEN BACK TO ALBUQUERQUE AS I TURNED N UP I-10 TOWARDS CHANDLER. REMAINDER OF FLT UNDER VFR WITH NO ISSUE. I HAVE PRIDED MYSELF ON GOOD ADM; HAVING FLOWN SINCE 1986; EVEN THOUGH I ONLY HAVE 600 HRS AND ABOUT 75 HRS OF IFR AT THE TIME OF THIS FLT. HOWEVER; I ALLOWED HAVING XM WX ONBOARD TO CONVINCE MYSELF THAT I HAD ENOUGH DATA TO CONDUCT THE FLT. HOWEVER; DUE TO 5-10 MIN DELAY IN RAPIDLY CHANGING WX; THE XM DATA WAS NOT CURRENT ENOUGH AND IS NO SUBSTITUTE FOR RADAR; WHICH I DID NOT HAVE ONBOARD THIS ACFT. MY SWITCH BACK TO GOOD POSITIVE ADM WAS TO IMMEDIATELY DEVIATE FROM MY CLRNC AND START THE 180 DEG TURN AS SOON AS I ENCOUNTERED ICING CONDITIONS. WITH THE UPDATED XM WX; A FEW MINS TOO LATE; SHOWING MIXED SNOW AND ICE ALONG MY RTE; WE WOULD NEVER HAVE SURVIVED HAD WE TAKEN THE 'WE CAN FLY THROUGH THIS' APCH. HAD I ALLOWED THE CLR SCREEN TO CONVINCE ME THAT I WOULD FLY THROUGH A SMALL CELL QUICKLY; WE WOULD HAVE BEEN 2 MINS INTO THE SNOW AND ICE BEFORE THE XM UPDATED WITH THE 4 MI TO RETURN; OR 20-30 MI OR MORE TO FLY THROUGH. I DON'T BELIEVE THE C182 WOULD HAVE STAYED AIRBORNE FOR EITHER OF THESE OPTIONS AT THE RATE THE ICE WAS BUILDING. I AM NOW A CFI AND SOON TO BE A CFII AND WILL BE PASSING THIS STORY ONTO MY STUDENTS; ESPECIALLY THOSE FLYING XM WX EQUIPPED ACFT. IT IS A GREAT TOOL TO LOOK AT WX; BUT IT IS NOT REAL TIME AND DOES COME WITH THE RISK OF OVER DEPENDENCE ON THE TECHNOLOGY. MY NONE-G1000 DECISION WOULD HAVE BEEN TO STAY IN A HOTEL IN EL PASO; THAT DECISION SHOULD HAVE CARRIED OVER INTO THE TAA G-1000 C182.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.