Narrative:

We filed V105 down to tucson and then V16 to silver city. After takeoff ATC asked if we could take V94 which we confirmed we could. Around 8;000 ft MSL we entered IMC. We sat in solid IMC for close to 1 hour straight before we popped out into a broken layer. We picked up very light rime ice during this phase of flight. About 40 miles west of the sso VOR we flew into a big puffy cloud and it plastered us with ice. Our OAT gauge stated the temperature was 38 degrees F (later I learned that the gauge was reading inaccurate.) this was the worst icing event I've ever encountered. We had pitot heat and carb heat on with mixture full rich during the encounter. The windshield was instantly iced over; and within 30 seconds the engine started sputtering. I informed ATC we had moderate icing and that we needed to descend. I was told unable due to the MEA being 10;000 ft which was our cruising altitude. He then asked if we could climb; but we were only making 1800 RPM with full power so I said unable. I waited another 15 seconds or so and made the PIC decision that we had to descend and turn around. I started a rapid steep turn back to where we had come from and descended way below the MEA. For about 15 seconds I actually thought we were going to fly into some kind of terrain. I asked abq center for vectors to the nearest airport and was given a heading to fly towards cochise county. After a few minutes on this heading I realized on my ipad with foreflight that it would take me straight into a mountain. I made a decision to turn back the other way and we eventually broke out of the clouds somewhere around 5-6;000 ft. I had to circle for a good 10 minutes to let the ice sublimate so that we could get our engine power back and create more lift for the airplane. I was asked if I needed to declare an emergency and that I could land on the highway right below us and that he would have trucks ready. I declined and ended up cancelling IFR and going to a nearby airport just up the valley VFR. I then called FSS to let the controller know we had safely landed. I should have declared an emergency the second we had that much ice. I think a big issue with pilots is that they fear declaring an emergency out of fear of repercussion. I am going to present a FAA safety seminar on this topic to discuss the event and the actions I could have taken to make it a better situation.

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Original NASA ASRS Text

Title: C172 instructor reports an inadvertent moderate icing encounter at 10;000 FT on V94 eastbound. With ice covering the windshield and the engine losing power the decision is made to reverse course as altitude cannot be held. During descent the iPad is consulted and terrain is noted ahead; resulting in another course reversal before breaking out into VMC.

Narrative: We filed V105 down to Tucson and then V16 to Silver City. After takeoff ATC asked if we could take V94 which we confirmed we could. Around 8;000 FT MSL we entered IMC. We sat in solid IMC for close to 1 hour straight before we popped out into a broken layer. We picked up very light rime ice during this phase of flight. About 40 miles west of the SSO VOR we flew into a big puffy cloud and it plastered us with ICE. Our OAT gauge stated the temperature was 38 degrees F (later I learned that the gauge was reading inaccurate.) This was the worst icing event I've ever encountered. We had pitot heat and carb heat on with mixture full rich during the encounter. The windshield was instantly iced over; and within 30 seconds the engine started sputtering. I informed ATC we had moderate icing and that we needed to descend. I was told unable due to the MEA being 10;000 FT which was our cruising altitude. He then asked if we could climb; but we were only making 1800 RPM with full power so I said unable. I waited another 15 seconds or so and made the PIC decision that we had to descend and turn around. I started a rapid steep turn back to where we had come from and descended way below the MEA. For about 15 seconds I actually thought we were going to fly into some kind of terrain. I asked ABQ Center for vectors to the nearest airport and was given a heading to fly towards Cochise County. After a few minutes on this heading I realized on my iPad with foreflight that it would take me straight into a mountain. I made a decision to turn back the other way and we eventually broke out of the clouds somewhere around 5-6;000 FT. I had to circle for a good 10 minutes to let the ice sublimate so that we could get our engine power back and create more lift for the airplane. I was asked if I needed to declare an emergency and that I could land on the highway right below us and that he would have trucks ready. I declined and ended up cancelling IFR and going to a nearby airport just up the valley VFR. I then called FSS to let the Controller know we had safely landed. I should have declared an emergency the second we had that much ice. I think a big issue with pilots is that they fear declaring an emergency out of fear of repercussion. I am going to present a FAA Safety Seminar on this topic to discuss the event and the actions I could have taken to make it a better situation.

Data retrieved from NASA's ASRS site as of July 2013 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.