Narrative:

I was tracking the localizer of hayward airport's localizer DME 28L approach at 6000 ft MSL about 18 mi out. Bay approach told me to cross 'brien' (11.9 DME) at or above 4000 ft MSL and cleared me for the approach. As I was descending, at about 14-15 DME out, the DME indication went out. I rechked all of my avionics to see if the problem was with my aircraft. Everything seemed set up correctly. The DME indication came back on at about 11.0 DME and I noticed I had already descended through 4000 ft MSL. In being distracted by the problematic DME indications, I may have descended slightly below 4000 ft MSL before 'brien' (11.9 DME). I advised bay of my previous DME problems and was then cleared to hayward tower frequency. As I continued on the approach the DME went out again for a short period of time. I again advised tower of the situation. I checked my DME after landing at hayward's ground check point and it worked correctly. In the past I have had similar situations with the DME on this approach. Furthermore, I have had discussions with other pilots in other aircraft who have experienced the same situation. Callback conversation with reporter revealed the following information: reporter states his DME in aircraft has been checked with no problem found. Hwd equipment on this DME approach has gone down for maintenance a couple of times. At about 12 DME the signal goes off and on, then at 7 mi seems to be a strong indication again. He was descending through actual IFR and night time when this occurred. Reporter quite upset due to high terrain at this area of the approach. Since he is not the only pilot who has experienced this, he feels it should be checked.

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Original NASA ASRS Text

Title: SMA EXPERIENCES INTERMITTENT DME INDICATIONS ON LOC DME APCH.

Narrative: I WAS TRACKING THE LOC OF HAYWARD ARPT'S LOC DME 28L APCH AT 6000 FT MSL ABOUT 18 MI OUT. BAY APCH TOLD ME TO CROSS 'BRIEN' (11.9 DME) AT OR ABOVE 4000 FT MSL AND CLRED ME FOR THE APCH. AS I WAS DSNDING, AT ABOUT 14-15 DME OUT, THE DME INDICATION WENT OUT. I RECHKED ALL OF MY AVIONICS TO SEE IF THE PROBLEM WAS WITH MY ACFT. EVERYTHING SEEMED SET UP CORRECTLY. THE DME INDICATION CAME BACK ON AT ABOUT 11.0 DME AND I NOTICED I HAD ALREADY DSNDED THROUGH 4000 FT MSL. IN BEING DISTRACTED BY THE PROBLEMATIC DME INDICATIONS, I MAY HAVE DSNDED SLIGHTLY BELOW 4000 FT MSL BEFORE 'BRIEN' (11.9 DME). I ADVISED BAY OF MY PREVIOUS DME PROBLEMS AND WAS THEN CLRED TO HAYWARD TWR FREQ. AS I CONTINUED ON THE APCH THE DME WENT OUT AGAIN FOR A SHORT PERIOD OF TIME. I AGAIN ADVISED TWR OF THE SITUATION. I CHKED MY DME AFTER LNDG AT HAYWARD'S GND CHK POINT AND IT WORKED CORRECTLY. IN THE PAST I HAVE HAD SIMILAR SITUATIONS WITH THE DME ON THIS APCH. FURTHERMORE, I HAVE HAD DISCUSSIONS WITH OTHER PLTS IN OTHER ACFT WHO HAVE EXPERIENCED THE SAME SITUATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES HIS DME IN ACFT HAS BEEN CHKED WITH NO PROBLEM FOUND. HWD EQUIP ON THIS DME APCH HAS GONE DOWN FOR MAINT A COUPLE OF TIMES. AT ABOUT 12 DME THE SIGNAL GOES OFF AND ON, THEN AT 7 MI SEEMS TO BE A STRONG INDICATION AGAIN. HE WAS DSNDING THROUGH ACTUAL IFR AND NIGHT TIME WHEN THIS OCCURRED. RPTR QUITE UPSET DUE TO HIGH TERRAIN AT THIS AREA OF THE APCH. SINCE HE IS NOT THE ONLY PLT WHO HAS EXPERIENCED THIS, HE FEELS IT SHOULD BE CHKED.

Data retrieved from NASA's ASRS site as of July 2007 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.