Narrative:

My student and I were on an instrument flight plan in the local cincinnati area for training purposes. At the time, we were being vectored for the NDB-a approach into the hamilton-fairfield airport in hamilton, oh. Cincinnati approach gave us a final vector to intercept the final approach course and told us to maintain 2500' until established, cleared for the approach. When we intercepted the final approach course we descended to 1700' as published on the approach plate. Once we reached that altitude, cincinnati approach told us that he had a low altitude alert on us and asked us our altimeter setting. Once he found that our setting was the same as his, nothing was said. Upon returning to our home base, I asked a more experienced local pilot than myself why approach might say what they did. I was told that when being vectored for the straight-in NDB-a approach at hamilton, you must remain at 2500' until crossing demur intersection. Not knowing what I know now, if being vectored for this approach one million times, I would still descend to 1700' upon interception of the final approach course every time. Something should be written on the approach plate stating the fact you should remain at 2500' until crossing demur. Another contributing factors was the controller's wording of the approach clearance ('maintain 2500' until established...'). Maybe it should be stated 'maintain 2500' until demur'. I wonder how many other apches like this one are out there waiting for me.

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Original NASA ASRS Text

Title: A CFI AND TRNEE RECEIVED A LOW ALT ALERT FROM APCH CTLR WHILE ON AN IMC PRACTICE NDB APCH. REPORTER ADMITS TO EARLY DESCENT BUT CLAIMS APCH PLATE IS OBSCURE IN DEFINITION.

Narrative: MY STUDENT AND I WERE ON AN INSTRUMENT FLT PLAN IN THE LCL CINCINNATI AREA FOR TRAINING PURPOSES. AT THE TIME, WE WERE BEING VECTORED FOR THE NDB-A APCH INTO THE HAMILTON-FAIRFIELD ARPT IN HAMILTON, OH. CINCINNATI APCH GAVE US A FINAL VECTOR TO INTERCEPT THE FINAL APCH COURSE AND TOLD US TO MAINTAIN 2500' UNTIL ESTABLISHED, CLRED FOR THE APCH. WHEN WE INTERCEPTED THE FINAL APCH COURSE WE DESCENDED TO 1700' AS PUBLISHED ON THE APCH PLATE. ONCE WE REACHED THAT ALT, CINCINNATI APCH TOLD US THAT HE HAD A LOW ALT ALERT ON US AND ASKED US OUR ALTIMETER SETTING. ONCE HE FOUND THAT OUR SETTING WAS THE SAME AS HIS, NOTHING WAS SAID. UPON RETURNING TO OUR HOME BASE, I ASKED A MORE EXPERIENCED LCL PLT THAN MYSELF WHY APCH MIGHT SAY WHAT THEY DID. I WAS TOLD THAT WHEN BEING VECTORED FOR THE STRAIGHT-IN NDB-A APCH AT HAMILTON, YOU MUST REMAIN AT 2500' UNTIL XING DEMUR INTXN. NOT KNOWING WHAT I KNOW NOW, IF BEING VECTORED FOR THIS APCH ONE MILLION TIMES, I WOULD STILL DSND TO 1700' UPON INTERCEPTION OF THE FINAL APCH COURSE EVERY TIME. SOMETHING SHOULD BE WRITTEN ON THE APCH PLATE STATING THE FACT YOU SHOULD REMAIN AT 2500' UNTIL XING DEMUR. ANOTHER CONTRIBUTING FACTORS WAS THE CTLR'S WORDING OF THE APCH CLRNC ('MAINTAIN 2500' UNTIL ESTABLISHED...'). MAYBE IT SHOULD BE STATED 'MAINTAIN 2500' UNTIL DEMUR'. I WONDER HOW MANY OTHER APCHES LIKE THIS ONE ARE OUT THERE WAITING FOR ME.

Data retrieved from NASA's ASRS site as of August 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.