Narrative:

Approach calls and asks for a runway 32 arrival for B747 heavy. I approved it. They bring in a gulfstream for runway 7R at the same time. They call back asking if I can maintain visual separation between the 2 aircraft. I tell them; only if the heavy is behind the gulfstream. It appeared to be a tie to the airport. The local controller asks the supervisor what his take on the situation. The supervisor says as long as the gulfstream is at taxiing speed it's a taxiing aircraft. The gulfstream lands and slows down to a taxiing speed. The heavy lands runway 32 in front of the gulfstream. Based on the supervisor's determination; the operation was allowed. Runways 7R and 32 do not physically intersect. Runway 7R has been used to taxi aircraft on in the past while landing runway 32. If there was more spacing between the 2 arrs; the gulfstream would have been past the point on runway 7R that the heavy would overfly. The gulfstream was slow enough on the runway to have been told to hold short of extended runway 32 edge; but was traveling slow enough that it was not going to pass that point until the heavy had passed it; so the instruction was not issued.

Related reports:

Google
 

Original NASA ASRS Text

Title: ANC TWR CTLR QUESTIONED SEPARATION UTILIZATION WITH HVY ACFT LNDG RWY 32 AND CIVIL JET'S PRIOR LNDG ON RWY 7R.

Narrative: APCH CALLS AND ASKS FOR A RWY 32 ARR FOR B747 HVY. I APPROVED IT. THEY BRING IN A GULFSTREAM FOR RWY 7R AT THE SAME TIME. THEY CALL BACK ASKING IF I CAN MAINTAIN VISUAL SEPARATION BTWN THE 2 ACFT. I TELL THEM; ONLY IF THE HVY IS BEHIND THE GULFSTREAM. IT APPEARED TO BE A TIE TO THE ARPT. THE LCL CTLR ASKS THE SUPVR WHAT HIS TAKE ON THE SITUATION. THE SUPVR SAYS AS LONG AS THE GULFSTREAM IS AT TAXIING SPD IT'S A TAXIING ACFT. THE GULFSTREAM LANDS AND SLOWS DOWN TO A TAXIING SPD. THE HVY LANDS RWY 32 IN FRONT OF THE GULFSTREAM. BASED ON THE SUPVR'S DETERMINATION; THE OP WAS ALLOWED. RWYS 7R AND 32 DO NOT PHYSICALLY INTERSECT. RWY 7R HAS BEEN USED TO TAXI ACFT ON IN THE PAST WHILE LNDG RWY 32. IF THERE WAS MORE SPACING BTWN THE 2 ARRS; THE GULFSTREAM WOULD HAVE BEEN PAST THE POINT ON RWY 7R THAT THE HVY WOULD OVERFLY. THE GULFSTREAM WAS SLOW ENOUGH ON THE RWY TO HAVE BEEN TOLD TO HOLD SHORT OF EXTENDED RWY 32 EDGE; BUT WAS TRAVELING SLOW ENOUGH THAT IT WAS NOT GOING TO PASS THAT POINT UNTIL THE HVY HAD PASSED IT; SO THE INSTRUCTION WAS NOT ISSUED.

Data retrieved from NASA's ASRS site as of January 2009 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.