Narrative:

I was working the south radar position when I observed a B747 on about a 1/2 mi final to runway 6R at an altitude of 1100 ft. During that time, I was working an IFR C172 at 2000 ft approximately 4 mi southeast of anc on a training flight from anc to ena. I commented to a co-worker, 'I hope the B747 doesn't go around' because of the altitude and proximity to the airport. The WX at the time was IFR. I observed the B747's mode C go from 1100 ft to 1400 ft and observed him in a right turn toward the C172. I immediately issued traffic to the C172 and his response was 'we're IMC.' the B747 was 1800 ft and 1 1/2 mi from the C172 and I issued an immediate right turn to a heading of 120 degrees and again issued traffic. The targets appeared to merge. After replaying the data, the B747 passed 400 ft over the C172. Anc tower was communicating with the B747. At the time of the incident, I was working light traffic. I believe that confusion in the flight deck about what heading to fly when issuing go around instructions and not clear understanding from foreign carriers. I do not know for sure, but had B747's TCASII been on, it would never had been that close.

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Original NASA ASRS Text

Title: A11 CTLR EXPERIENCED NMAC AT 2000 FT AS FOREIGN ACR FAILS TO COMPLY WITH GAR INSTRUCTIONS.

Narrative: I WAS WORKING THE S RADAR POS WHEN I OBSERVED A B747 ON ABOUT A 1/2 MI FINAL TO RWY 6R AT AN ALT OF 1100 FT. DURING THAT TIME, I WAS WORKING AN IFR C172 AT 2000 FT APPROX 4 MI SE OF ANC ON A TRAINING FLT FROM ANC TO ENA. I COMMENTED TO A CO-WORKER, 'I HOPE THE B747 DOESN'T GO AROUND' BECAUSE OF THE ALT AND PROX TO THE ARPT. THE WX AT THE TIME WAS IFR. I OBSERVED THE B747'S MODE C GO FROM 1100 FT TO 1400 FT AND OBSERVED HIM IN A R TURN TOWARD THE C172. I IMMEDIATELY ISSUED TFC TO THE C172 AND HIS RESPONSE WAS 'WE'RE IMC.' THE B747 WAS 1800 FT AND 1 1/2 MI FROM THE C172 AND I ISSUED AN IMMEDIATE R TURN TO A HDG OF 120 DEGS AND AGAIN ISSUED TFC. THE TARGETS APPEARED TO MERGE. AFTER REPLAYING THE DATA, THE B747 PASSED 400 FT OVER THE C172. ANC TWR WAS COMMUNICATING WITH THE B747. AT THE TIME OF THE INCIDENT, I WAS WORKING LIGHT TFC. I BELIEVE THAT CONFUSION IN THE FLT DECK ABOUT WHAT HDG TO FLY WHEN ISSUING GAR INSTRUCTIONS AND NOT CLR UNDERSTANDING FROM FOREIGN CARRIERS. I DO NOT KNOW FOR SURE, BUT HAD B747'S TCASII BEEN ON, IT WOULD NEVER HAD BEEN THAT CLOSE.

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.