Narrative:

I requested a local IFR clearance to shoot a series of approaches in a cessna 150 commuter equipped with a garmin 430. I was cleared to the initial approach fix at to climb to 3;000 ft (this was to be a demonstration for my student). After climbing through 850 ft MSL I was directed to contact departure. Departure cleared me to 3;000 ft and direct to [the] IAF for the ILS approach. All initially went well. I then noted that my heading indicator was rotating freely. I asked my student to see if he could get it to stop and set it for the same heading shown in trk on the GPS. We could not get it to stop. We then noted that the turn coordinator was not functioning correctly (it returned some time later). In the absence of a heading indicator; I changed the 430 to navigation screen 1 to match the direct heading with the indicated tracking heading. However; we learned that it was also moving about and did not match the compass.ATC asked me to report my altitude and noted that they did not have a primary radar reading on my airplane. Shortly after; I declared that I was in a 'no gyro' situation and needed assistance. They vectored me on a heading of 270 and ask that I climb to 4;000 ft to see if they could get a radar reading on me. I entered a climb but had great difficulty stabilizing my heading. At times the artificial horizon and turn coordinators worked sporadically. At 4000' I broke out of the clouds and was able to stabilize heading and climb with pilotage. ATC asked me to climb to 8;000 ft on 270 degree. I replied that I was unable in that airplane but would continue to climb. At 5;000 ft ATC directed me to turn to a heading of 180 degrees. I was able to do so with the systems operating; mostly compass. After a couple of minutes I noted the localizer for the ILS approach coming in and reported that to ATC. They asked if I was established. I replied I would be in I turned inbound immediately. The cleared me to do so and I tracked the localizer inbound. ATC then cleared me to descend to 3;000 ft. Shortly thereafter; they told me to not respond to future instructions and began reporting distance from airport and the desired altitude. I slowed the airplane and descended to intersect the glideslope. I broke out of IMC at 700 ft AGL prior to the threshold and was cleared to land and directed to contact ground on rollout.I believe I flew this mission to the best of my ability given the number of systems that were not working in the aircraft. During preflight and during the flight; the gauges indicated I had normal vacuum and electrical charge. ATC personnel met me at the airplane and we had a long discussion of what happened and I thanked them profusely for their professionalism and help. ATC also reported that they only had radar contact briefly during the flight and then again when I broke out of the clouds on final. The navigation and transponder systems were 'squawked' and the FBO manager informed of the incident that the airplane is currently not safe to fly.

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Original NASA ASRS Text

Title: C150 instructor pilot reported an intermittent transponder and loss of heading information in IFR conditions; and returned to the field with some help from ATC.

Narrative: I requested a local IFR clearance to shoot a series of approaches in a Cessna 150 Commuter equipped with a Garmin 430. I was cleared to the initial approach fix at to climb to 3;000 FT (this was to be a demonstration for my student). After climbing through 850 FT MSL I was directed to contact departure. Departure cleared me to 3;000 FT and direct to [the] IAF for the ILS approach. All initially went well. I then noted that my heading indicator was rotating freely. I asked my student to see if he could get it to stop and set it for the same heading shown in TRK on the GPS. We could not get it to stop. We then noted that the turn coordinator was not functioning correctly (it returned some time later). In the absence of a heading indicator; I changed the 430 to NAV screen 1 to match the direct heading with the indicated tracking heading. However; we learned that it was also moving about and did not match the compass.ATC asked me to report my altitude and noted that they did not have a primary radar reading on my airplane. Shortly after; I declared that I was in a 'no gyro' situation and needed assistance. They vectored me on a heading of 270 and ask that I climb to 4;000 FT to see if they could get a radar reading on me. I entered a climb but had great difficulty stabilizing my heading. At times the artificial horizon and turn coordinators worked sporadically. At 4000' I broke out of the clouds and was able to stabilize heading and climb with pilotage. ATC asked me to climb to 8;000 FT on 270 degree. I replied that I was unable in that airplane but would continue to climb. At 5;000 FT ATC directed me to turn to a heading of 180 degrees. I was able to do so with the systems operating; mostly compass. After a couple of minutes I noted the localizer for the ILS approach coming in and reported that to ATC. They asked if I was established. I replied I would be in I turned inbound immediately. The cleared me to do so and I tracked the localizer inbound. ATC then cleared me to descend to 3;000 FT. Shortly thereafter; they told me to not respond to future instructions and began reporting distance from airport and the desired altitude. I slowed the airplane and descended to intersect the glideslope. I broke out of IMC at 700 FT AGL prior to the threshold and was cleared to land and directed to contact ground on rollout.I believe I flew this mission to the best of my ability given the number of systems that were not working in the aircraft. During preflight and during the flight; the gauges indicated I had normal vacuum and electrical charge. ATC personnel met me at the airplane and we had a long discussion of what happened and I thanked them profusely for their professionalism and help. ATC also reported that they only had radar contact briefly during the flight and then again when I broke out of the clouds on final. The NAV and transponder systems were 'squawked' and the FBO manager informed of the incident that the airplane is currently not safe to fly.

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.