Narrative:

While in the mri runway 24 pattern, a helicopter passed from right to left directly under us. The estimated altitude of the helicopter was 600 ft MSL, our estimated altitude was 750 ft MSL at the time of crossing. I was in the left seat observing a CFI applicant/student who was flying in the right seat. No traffic calls were issued by tower. The helicopter was likely arriving on a golf course arrival that calls for that flight path and altitude, which conflicts with the standard left traffic pattern for runway 24. The student didn't see the helicopter at all, and I saw it only after it had passed under us and was clear to the west of us. The helicopter is painted with a color that makes it difficult to see in the city ground clutter. I believe increased helicopter operations and the desire to apply noise abatement policy and procedures have created an unsafe operating practice. Supplemental information from acn 628456: we were both looking in all directions for other traffic. Had we been informed that a helicopter was going to be coming from behind us and 100 ft below us, we could/would have extended our downwind and leveled off.

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Original NASA ASRS Text

Title: A C172 WITH A CFI AND CFI APPLICANT HAVE AN NMAC WITH A HELI WHILE IN MRI TWR'S AIRSPACE.

Narrative: WHILE IN THE MRI RWY 24 PATTERN, A HELI PASSED FROM R TO L DIRECTLY UNDER US. THE ESTIMATED ALT OF THE HELI WAS 600 FT MSL, OUR ESTIMATED ALT WAS 750 FT MSL AT THE TIME OF XING. I WAS IN THE L SEAT OBSERVING A CFI APPLICANT/STUDENT WHO WAS FLYING IN THE R SEAT. NO TFC CALLS WERE ISSUED BY TWR. THE HELI WAS LIKELY ARRIVING ON A GOLF COURSE ARR THAT CALLS FOR THAT FLT PATH AND ALT, WHICH CONFLICTS WITH THE STANDARD L TFC PATTERN FOR RWY 24. THE STUDENT DIDN'T SEE THE HELI AT ALL, AND I SAW IT ONLY AFTER IT HAD PASSED UNDER US AND WAS CLR TO THE W OF US. THE HELI IS PAINTED WITH A COLOR THAT MAKES IT DIFFICULT TO SEE IN THE CITY GND CLUTTER. I BELIEVE INCREASED HELI OPS AND THE DESIRE TO APPLY NOISE ABATEMENT POLICY AND PROCS HAVE CREATED AN UNSAFE OPERATING PRACTICE. SUPPLEMENTAL INFO FROM ACN 628456: WE WERE BOTH LOOKING IN ALL DIRECTIONS FOR OTHER TFC. HAD WE BEEN INFORMED THAT A HELI WAS GOING TO BE COMING FROM BEHIND US AND 100 FT BELOW US, WE COULD/WOULD HAVE EXTENDED OUR DOWNWIND AND LEVELED OFF.

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.