Narrative:

I was working a navajo inbound to merrill field from the northwest. The weather was IFR at anchorage international but VFR at merrill; and the pilot requested the GPS-a approach to mri. When the navajo was about 10 miles from yohoe (if); I cleared him for his approach into merrill. I was watching the south controller who was working a beech 1900 in sequence to anchorage international for the ILS runway 7L. The beech 1900 was on; basically; an opposing base to the navajo; though to different airports; the if and FAF's are closely spaced so I was keeping an eye on how close they would get. Yohoe is placed only about 2.5 miles from the anc 7L/7R finals. Knowing they are close; I looked at the beech 1900 on right base descending to 1;600 from 3;000 ft. I noted the beech 1900's speed and saw he was not going to be ahead of the navajo at yohoe to sufficiently stay 3 miles away from him; so I canceled and re-cleared the navajo to intercept the GPS-a to mri inside yohoe which would ensure we kept 3 miles between our two finals. I brought this to the attention of the south controller who was watching the situation evolve as well. The navajo took the new approach clearance and flew a few miles before went right through the final approach course for the GPS-a to mri and continued on the 090 degrees heading I gave him to intercept. This put him back on a converging course with the beech 1900 abeam him; on final for anc 7L ILS; at the same altitude and less than 3 miles away; I'm guessing about 2.5 miles or so. As the navajo 'went through' I told the south controller about it and he immediately canceled the beech 1900's approach clearance and turned them south for re-sequencing as I turned the navajo to a 040 heading to join the GPS-a final approach course. Wake turbulence was not an issue. Visual separation would not have been an option as an 'out' because we were IFR in that area with -sn 1SM advertised visibility and RVR's. It would be nice if either yohoe was moved closer to rickr so it didn't impede on the anc final(s) or create a new fix altogether that was closer to rickr to prevent this kind of set-up for conflict. Also; I could have and should have just cleared the navajo north of yohoe on an intercept closer to rickr so that if he did go through; I wouldn't lose separation with the anc final!

Related reports:

Google
 

Original NASA ASRS Text

Title: A11 Controller lost separation between an IFR GPS-A arrival to MRI and an aircraft on the ILS 7L Approach to ANC. The MRI arrival flew through the final approach course.

Narrative: I was working a Navajo inbound to Merrill Field from the northwest. The weather was IFR at Anchorage International but VFR at Merrill; and the pilot requested the GPS-A Approach to MRI. When the Navajo was about 10 miles from YOHOE (IF); I cleared him for his approach into Merrill. I was watching the South Controller who was working a Beech 1900 in sequence to Anchorage International for the ILS Runway 7L. The Beech 1900 was on; basically; an opposing base to the Navajo; though to different airports; the IF and FAF's are closely spaced so I was keeping an eye on how close they would get. YOHOE is placed only about 2.5 miles from the ANC 7L/7R finals. Knowing they are close; I looked at the Beech 1900 on right base descending to 1;600 from 3;000 FT. I noted the Beech 1900's speed and saw he was not going to be ahead of the Navajo at YOHOE to sufficiently stay 3 miles away from him; so I canceled and re-cleared the Navajo to intercept the GPS-A to MRI inside YOHOE which would ensure we kept 3 miles between our two finals. I brought this to the attention of the South Controller who was watching the situation evolve as well. The Navajo took the new approach clearance and flew a few miles before went right through the final approach course for the GPS-A to MRI and continued on the 090 degrees heading I gave him to intercept. This put him back on a converging course with the Beech 1900 abeam him; on final for ANC 7L ILS; at the same altitude and less than 3 miles away; I'm guessing about 2.5 miles or so. As the Navajo 'went through' I told the South Controller about it and he immediately canceled the Beech 1900's approach clearance and turned them south for re-sequencing as I turned the Navajo to a 040 heading to join the GPS-A final approach course. Wake turbulence was not an issue. Visual separation would not have been an option as an 'out' because we were IFR in that area with -SN 1SM advertised visibility and RVR's. It would be nice if either YOHOE was moved closer to RICKR so it didn't impede on the ANC final(s) or create a new fix altogether that was closer to RICKR to prevent this kind of set-up for conflict. Also; I could have and should have just cleared the Navajo north of YOHOE on an intercept closer to RICKR so that if he did go through; I wouldn't lose separation with the ANC final!

Data retrieved from NASA's ASRS site as of April 2012 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.