Narrative:

We were radar vectored to the final VOR runway 13 sns. Student was using the mr beacon to identify 'sames' intersection. When we reached 'sames' (the final approach fix), we started our descent to the MDA (500 ft) and informed sns tower. A few mins later, tower called and said monterey told him we were 1 mi outside of 'sames' and below assigned altitude. I rechked the ADF and, according to the ADF, we were well inside 'sames.' I also had a visual on the runway and we were closer than 5 mi. Tower also said monterey showed us at 600 ft, but we were still at 900-1000 ft MSL. The altitude setting was then checked and was correct. We then went missed and monterey explained why he told tower about our course. I informed him of my intentions to check the equipment at the watsonville NDB (pajar). Nothing more was mentioned. We held at 'pajar' and noted some anomalies with the ADF. The ADF was written up upon return. I mentioned this incident to my chief instructor and he said he had the same problem twice recently. He then instructed all instructors to have monterey call 'sames' intersection from now on in non-DME aircraft. Callback conversation with reporter revealed the following information: the reporter is an instructor for a large flight school at sjc. His school uses the C-172 and piper warrior for instrument training. This incident happened in a C-172, and the reporter has seen similar incidents in several aircraft of both types. As the 'mr' beacon is about 19 NM from 'sames' intersection, the ADF needle will swing back and forth about 10 degrees making the identify of 'sames' very difficult and imprecise for aircraft that do not have DME. The reporter believes that 'ADF or DME required' should be replaced with 'radar or DME required' and all reference to the 'mr' NDB be removed from the approach chart. The policy of the flight school now is to ask for a radar fix over 'sames.'

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Original NASA ASRS Text

Title: ALTDEV, SMA LOW OVER FINAL APCH FIX ON A PRACTICE VOR APCH.

Narrative: WE WERE RADAR VECTORED TO THE FINAL VOR RWY 13 SNS. STUDENT WAS USING THE MR BEACON TO IDENT 'SAMES' INTXN. WHEN WE REACHED 'SAMES' (THE FINAL APCH FIX), WE STARTED OUR DSCNT TO THE MDA (500 FT) AND INFORMED SNS TWR. A FEW MINS LATER, TWR CALLED AND SAID MONTEREY TOLD HIM WE WERE 1 MI OUTSIDE OF 'SAMES' AND BELOW ASSIGNED ALT. I RECHKED THE ADF AND, ACCORDING TO THE ADF, WE WERE WELL INSIDE 'SAMES.' I ALSO HAD A VISUAL ON THE RWY AND WE WERE CLOSER THAN 5 MI. TWR ALSO SAID MONTEREY SHOWED US AT 600 FT, BUT WE WERE STILL AT 900-1000 FT MSL. THE ALT SETTING WAS THEN CHKED AND WAS CORRECT. WE THEN WENT MISSED AND MONTEREY EXPLAINED WHY HE TOLD TWR ABOUT OUR COURSE. I INFORMED HIM OF MY INTENTIONS TO CHK THE EQUIP AT THE WATSONVILLE NDB (PAJAR). NOTHING MORE WAS MENTIONED. WE HELD AT 'PAJAR' AND NOTED SOME ANOMALIES WITH THE ADF. THE ADF WAS WRITTEN UP UPON RETURN. I MENTIONED THIS INCIDENT TO MY CHIEF INSTRUCTOR AND HE SAID HE HAD THE SAME PROB TWICE RECENTLY. HE THEN INSTRUCTED ALL INSTRUCTORS TO HAVE MONTEREY CALL 'SAMES' INTXN FROM NOW ON IN NON-DME ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR IS AN INSTRUCTOR FOR A LARGE FLT SCHOOL AT SJC. HIS SCHOOL USES THE C-172 AND PIPER WARRIOR FOR INST TRAINING. THIS INCIDENT HAPPENED IN A C-172, AND THE RPTR HAS SEEN SIMILAR INCIDENTS IN SEVERAL ACFT OF BOTH TYPES. AS THE 'MR' BEACON IS ABOUT 19 NM FROM 'SAMES' INTXN, THE ADF NEEDLE WILL SWING BACK AND FORTH ABOUT 10 DEGS MAKING THE IDENT OF 'SAMES' VERY DIFFICULT AND IMPRECISE FOR ACFT THAT DO NOT HAVE DME. THE RPTR BELIEVES THAT 'ADF OR DME REQUIRED' SHOULD BE REPLACED WITH 'RADAR OR DME REQUIRED' AND ALL REF TO THE 'MR' NDB BE REMOVED FROM THE APCH CHART. THE POLICY OF THE FLT SCHOOL NOW IS TO ASK FOR A RADAR FIX OVER 'SAMES.'

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.