Narrative:

A flight was planned for a student to demonstrate actual IFR conditions. We filed for 2;000 ft to stay out of possible icing. 3;000 ft was; however; assigned in our clearance and then 4;000 ft was assigned once airborne and in contact with ATC. At approximately 3;500 ft we began to collect ice and at 4;000 ft rime followed by mixed icing began to accumulate rapidly. We attempted to coordinate another altitude and ATC suggested a climb; but we had not experienced any icing until around 3;500 ft so a climb into possible worse icing seemed like a bad idea. I instead asked for a lower altitude. We were given and descended to 3;000 ft where the ice seemed to stop collecting however; when we were vectored south; the ice began to accumulate once again. ATC was vectoring another aircraft into ZZZ and could not put us close to it due to IFR separation requirements. We began to pick up ice on the windshield and the visible icing on the wing struts continued to accumulate. As the ice continued to accumulate I asked for a lower altitude; 2;000 ft MSL; to get us out of the icing as soon as possible. I asked for 2;000 ft; where I knew there was no icing. However; ATC was unable as this was below his minimum vectoring altitude. It was at this point I decided to declare an emergency. We were given 2;500 ft and vectors closer to the field and the icing on the plane began to noticeably dissipate. With the ice melting away from the aircraft; the situation improved a great deal. We began to gain ground contact and were vectored onto and intercepted the localizer. We notified ATC we were established and were then cleared for the approach. Out of 2;000 ft we gained even better ground contact and finally broke into the clear around 1;200 ft. We flew the ILS with no incident and taxied to the ramp. In retrospect; I could have demonstrated better judgment during this event. I do feel; however; I declared the emergency at a time that best allowed for a favorable outcome. Further delay of this decision could have proven otherwise. The performance of all involved--pilots and ATC--was excellent. ATC handled the matter very calmly and was a great help.

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Original NASA ASRS Text

Title: An instruction flight; intended to expose the instrument student to actual conditions; encountered icing conditions and the instructor declared an emergency to expedite their exit from the condition.

Narrative: A flight was planned for a student to demonstrate actual IFR conditions. We filed for 2;000 FT to stay out of possible icing. 3;000 FT was; however; assigned in our clearance and then 4;000 FT was assigned once airborne and in contact with ATC. At approximately 3;500 FT we began to collect ice and at 4;000 FT rime followed by mixed icing began to accumulate rapidly. We attempted to coordinate another altitude and ATC suggested a climb; but we had not experienced any icing until around 3;500 FT so a climb into possible worse icing seemed like a bad idea. I instead asked for a lower altitude. We were given and descended to 3;000 FT where the ice seemed to stop collecting however; when we were vectored south; the ice began to accumulate once again. ATC was vectoring another aircraft into ZZZ and could not put us close to it due to IFR separation requirements. We began to pick up ice on the windshield and the visible icing on the wing struts continued to accumulate. As the ice continued to accumulate I asked for a lower altitude; 2;000 FT MSL; to get us out of the icing ASAP. I asked for 2;000 FT; where I knew there was no icing. However; ATC was unable as this was below his minimum vectoring altitude. It was at this point I decided to declare an emergency. We were given 2;500 FT and vectors closer to the field and the icing on the plane began to noticeably dissipate. With the ice melting away from the aircraft; the situation improved a great deal. We began to gain ground contact and were vectored onto and intercepted the localizer. We notified ATC we were established and were then cleared for the approach. Out of 2;000 FT we gained even better ground contact and finally broke into the clear around 1;200 FT. We flew the ILS with no incident and taxied to the ramp. In retrospect; I could have demonstrated better judgment during this event. I do feel; however; I declared the emergency at a time that best allowed for a favorable outcome. Further delay of this decision could have proven otherwise. The performance of all involved--pilots and ATC--was excellent. ATC handled the matter very calmly and was a great help.

Data retrieved from NASA's ASRS site as of April 2012 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.