Narrative:

ATIS was calling the WX about 2500 ft overcast, 10 mi visibility, winds 320 degrees gusting to 13 KTS, simultaneous approachs runway 27L&right. We were talking with approach and told to expect the left side. We briefed the approach. After several turns because of heavy traffic and a descent to 5000 ft, we were cleared for the ILS runway 27L, 5000 ft until established, 170 KTS to willt, call the tower at willt, 120.75, caution, wake turbulence, you're following a B727. At this point, we were just outside wavie, and decided to fly a little high on the GS and 1/2 - 1 DOT upwind to avoid the preceding aircraft's wake. Tops were about 8000 ft variable, so we were IMC. While descending through about 4700 ft MSL, the monitor controller said 'turn left immediately, do not descend, climb to 5000 ft, maintain 5000 ft until on the localizer. You are close to an aircraft (or words to that effect) on the ILS runway 27R.' we complied immediately, reintercepted, and continued the approach uneventfully. Having flown all around the united states during the past 20 yrs, I consider the ord controllers among the best. I have also flown into and out of ord hundreds of times, using the same technique, but this was the first time I had received an alert from a monitor. Although still puzzled by the seeming contradiction between wake avoidance and protected airspace, other pilots I spoke with later said they would have stayed on the localizer, but flown high on the GS. Perhaps this can benefit someone else.

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Original NASA ASRS Text

Title: A KING AIR TURBO DEVIATES FROM THE ILS COURSE AND GS ON AN APCH TO ORD RWY 27L TO AVOID WAKE TURB OF A B727 AHEAD. VECTORED OFF BY APCH FOR ANOTHER TRY.

Narrative: ATIS WAS CALLING THE WX ABOUT 2500 FT OVCST, 10 MI VISIBILITY, WINDS 320 DEGS GUSTING TO 13 KTS, SIMULTANEOUS APCHS RWY 27L&R. WE WERE TALKING WITH APCH AND TOLD TO EXPECT THE L SIDE. WE BRIEFED THE APCH. AFTER SEVERAL TURNS BECAUSE OF HVY TFC AND A DSCNT TO 5000 FT, WE WERE CLRED FOR THE ILS RWY 27L, 5000 FT UNTIL ESTABLISHED, 170 KTS TO WILLT, CALL THE TWR AT WILLT, 120.75, CAUTION, WAKE TURB, YOU'RE FOLLOWING A B727. AT THIS POINT, WE WERE JUST OUTSIDE WAVIE, AND DECIDED TO FLY A LITTLE HIGH ON THE GS AND 1/2 - 1 DOT UPWIND TO AVOID THE PRECEDING ACFT'S WAKE. TOPS WERE ABOUT 8000 FT VARIABLE, SO WE WERE IMC. WHILE DSNDING THROUGH ABOUT 4700 FT MSL, THE MONITOR CTLR SAID 'TURN L IMMEDIATELY, DO NOT DSND, CLB TO 5000 FT, MAINTAIN 5000 FT UNTIL ON THE LOC. YOU ARE CLOSE TO AN ACFT (OR WORDS TO THAT EFFECT) ON THE ILS RWY 27R.' WE COMPLIED IMMEDIATELY, REINTERCEPTED, AND CONTINUED THE APCH UNEVENTFULLY. HAVING FLOWN ALL AROUND THE UNITED STATES DURING THE PAST 20 YRS, I CONSIDER THE ORD CTLRS AMONG THE BEST. I HAVE ALSO FLOWN INTO AND OUT OF ORD HUNDREDS OF TIMES, USING THE SAME TECHNIQUE, BUT THIS WAS THE FIRST TIME I HAD RECEIVED AN ALERT FROM A MONITOR. ALTHOUGH STILL PUZZLED BY THE SEEMING CONTRADICTION BTWN WAKE AVOIDANCE AND PROTECTED AIRSPACE, OTHER PLTS I SPOKE WITH LATER SAID THEY WOULD HAVE STAYED ON THE LOC, BUT FLOWN HIGH ON THE GS. PERHAPS THIS CAN BENEFIT SOMEONE ELSE.

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.