Narrative:

IFR flight plan filed due to IFR conditions at destination airport and no active IFR procedure available due to construction at pdx. Upon reaching a point 2 miles inside the hanna on the ILS the single glideslope failed. The aircraft had been flying in moderate rain during vectoring for the approach (I was number 5 for the approach). At the time of the failure of the glideslope I was in visual conditions with ground reference and the pdx airport was in IFR conditions in passing rain showers. The airport had been VFR briefly during the previous few minutes. I continued flying the localizer with ground reference toward the runway but not on the glideslope. The tower asked me to check altitude and also asked if I had ground reference. I told them my glideslope was questionable and that I had ground reference. I continued to the runway in VFR conditions with the airport reporting IFR. The tower called me on landing and was concerned to know the conditions under which I landed and whether their equipment might have been at fault. I responded with the explanation stated here and there appeared to be no further concern. Their complaint was that I didn't keep them in the loop. My comment was that I was pretty busy and just wanted to get on the ground safely. The aircraft is now in the radio shop. The receiver was checked ok so the tech suspects moisture somewhere in the antennae system.

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Original NASA ASRS Text

Title: A single engine aircraft pilot continued an ILS approach using ground reference in IMC after the aircraft's glideslope apparently failed. The aircraft flew below the glideslope and ATC questioned the pilot's actions.

Narrative: IFR flight plan filed due to IFR conditions at destination airport and no active IFR procedure available due to construction at PDX. Upon reaching a point 2 miles inside the HANNA on the ILS the single glideslope failed. The aircraft had been flying in moderate rain during vectoring for the approach (I was number 5 for the approach). At the time of the failure of the glideslope I was in visual conditions with ground reference and the PDX airport was in IFR conditions in passing rain showers. The airport had been VFR briefly during the previous few minutes. I continued flying the localizer with ground reference toward the runway but not on the glideslope. The tower asked me to check altitude and also asked if I had ground reference. I told them my glideslope was questionable and that I had ground reference. I continued to the runway in VFR conditions with the airport reporting IFR. The tower called me on landing and was concerned to know the conditions under which I landed and whether their equipment might have been at fault. I responded with the explanation stated here and there appeared to be no further concern. Their complaint was that I didn't keep them in the loop. My comment was that I was pretty busy and just wanted to get on the ground safely. The aircraft is now in the radio shop. The receiver was checked ok so the tech suspects moisture somewhere in the antennae system.

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.