Narrative:

While practicing approachs at cno, controller gave a vector of 360 degrees to 350 degrees. This is usually the second to last vector to intercept final for the ILS runway 26R approach at cno. However, the controller did not inform us that it was a vector across final until I made a radio call to get the controller's attention. We flew clearly through the localizer at 3000 ft and then the controller gave us instructions to turn left to 210 degrees, intercept the localizer at or above 2100 ft cleared for the approach. I then read back the instructions, '210 degrees, 2100 ft, cleared for the approach.' my student queried me because the clearance to descend to 2100 ft was not a normal clearance. I pointed out on the approach plate that the mdh between lindn intersection and dewye was 2100 ft. We descended to 2100 ft to intercept the GS, and when we began leveling off, the controller called back and advised that we were told to descend to 2800 ft and that we had a traffic alert for a mooney shooting the ILS runway 9 approach at riverside. I replied that I heard 2100 ft and read back 2100 ft, but would climb immediately to 2800 ft. As I climbed, I saw the traffic, which we may have hit if I would have remained at 2100 ft. I believe the error was caused by the controller, but also believe it is very dangerous to allow practice approachs at these airports simultaneously.

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Original NASA ASRS Text

Title: AN INSTRUCTOR PLT AND PVT PLT IN A PA34 ON AN ILS TO RWY 26R AT CNO HAVE A POTENTIAL CONFLICT WITH AN OPPOSITE DIRECTION MOONEY AT 2500 FT ON AN ILS APCH TO RWY 9 AT RAL, CA.

Narrative: WHILE PRACTICING APCHS AT CNO, CTLR GAVE A VECTOR OF 360 DEGS TO 350 DEGS. THIS IS USUALLY THE SECOND TO LAST VECTOR TO INTERCEPT FINAL FOR THE ILS RWY 26R APCH AT CNO. HOWEVER, THE CTLR DID NOT INFORM US THAT IT WAS A VECTOR ACROSS FINAL UNTIL I MADE A RADIO CALL TO GET THE CTLR'S ATTN. WE FLEW CLRLY THROUGH THE LOC AT 3000 FT AND THEN THE CTLR GAVE US INSTRUCTIONS TO TURN L TO 210 DEGS, INTERCEPT THE LOC AT OR ABOVE 2100 FT CLRED FOR THE APCH. I THEN READ BACK THE INSTRUCTIONS, '210 DEGS, 2100 FT, CLRED FOR THE APCH.' MY STUDENT QUERIED ME BECAUSE THE CLRNC TO DSND TO 2100 FT WAS NOT A NORMAL CLRNC. I POINTED OUT ON THE APCH PLATE THAT THE MDH BTWN LINDN INTXN AND DEWYE WAS 2100 FT. WE DSNDED TO 2100 FT TO INTERCEPT THE GS, AND WHEN WE BEGAN LEVELING OFF, THE CTLR CALLED BACK AND ADVISED THAT WE WERE TOLD TO DSND TO 2800 FT AND THAT WE HAD A TFC ALERT FOR A MOONEY SHOOTING THE ILS RWY 9 APCH AT RIVERSIDE. I REPLIED THAT I HEARD 2100 FT AND READ BACK 2100 FT, BUT WOULD CLB IMMEDIATELY TO 2800 FT. AS I CLBED, I SAW THE TFC, WHICH WE MAY HAVE HIT IF I WOULD HAVE REMAINED AT 2100 FT. I BELIEVE THE ERROR WAS CAUSED BY THE CTLR, BUT ALSO BELIEVE IT IS VERY DANGEROUS TO ALLOW PRACTICE APCHS AT THESE ARPTS SIMULTANEOUSLY.

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.