Narrative:

Flight was in cruise; turbulence was moderate with strong mountain wave which was causing difficulty maintaining within three hundred feet of assigned altitude. Talking to controller and aircraft in front on same course that reported ice at 8;500 and above and bases at 8;500. Descended from MEA of 9;000 from IMC to VFR conditions. Outside air temp was 5c during descent and temp was reported to controller. Enter VFR conditions for around 5 min just below bases could see due to lights from city below and behind. At that time turbulence increased and large down draft accompanied by rain started. It was above freezing but it built up immediately. Thinking super cooled water droplets. Pitot heat was applied immediately but was overwhelmed and airspeed was lost. Ice was building quickly. Turbulence and wave were very intense. Control was maintained but course and altitude varied during static failure seemed like a long time; looking at the flight aware track the time was probably less than a few seconds. Controller issued a turn clearance for terrain 350. Made two calls to ATC for a turn back to airport. One other aircraft responded to my call and center then responded with vectors back to airport. I believe either the ice built up on antenna or the radio was bumped; I appeared to lose radio for a short moment switch coms and contact was restored. Thank controller for his help and cancel IFR and landing was performed. Ice melted; flight resumed few minutes later VFR without event. Fixed base operator contacted said controller gave number to call. I have been flying for over 30 years in the IFR system and have experienced icing but never as it started right there on me. From nothing with 10 plus visibility to intense freezing rain above freezing level. Hearing the other aircraft in front of me there was no cause for concern. Contributing factor was turning pitot heat off when entering VFR conditions; losing airspeed caused losing focus at a very bad time.

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Original NASA ASRS Text

Title: Grumman-American AA5 Pilot reported encountering icing conditions while on an IFR flight plan; descended and diverted for non eventful landing.

Narrative: Flight was in cruise; turbulence was moderate with strong mountain wave which was causing difficulty maintaining within three hundred feet of assigned altitude. Talking to Controller and aircraft in front on same course that reported ice at 8;500 and above and bases at 8;500. Descended from MEA of 9;000 from IMC to VFR conditions. Outside air temp was 5c during descent and temp was reported to controller. Enter VFR conditions for around 5 min just below bases could see due to lights from city below and behind. At that time turbulence increased and large down draft accompanied by rain started. It was above freezing but it built up immediately. Thinking super cooled water droplets. Pitot heat was applied immediately but was overwhelmed and airspeed was lost. Ice was building quickly. Turbulence and wave were very intense. Control was maintained but course and altitude varied during static failure seemed like a long time; looking at the flight aware track the time was probably less than a few seconds. Controller issued a turn clearance for terrain 350. Made two calls to ATC for a turn back to airport. One other aircraft responded to my call and center then responded with vectors back to airport. I believe either the ice built up on antenna or the radio was bumped; I appeared to lose radio for a short moment switch coms and contact was restored. Thank Controller for his help and cancel IFR and landing was performed. Ice melted; flight resumed few minutes later VFR without event. Fixed base operator contacted said Controller gave number to call. I have been flying for over 30 years in the IFR system and have experienced icing but never as it started right there on me. From nothing with 10 plus visibility to intense freezing rain above freezing level. Hearing the other aircraft in front of me there was no cause for concern. Contributing factor was turning pitot heat off when entering VFR conditions; losing airspeed caused losing focus at a very bad time.

Data retrieved from NASA's ASRS site 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.