TRACON controller described a pilot filed near midair collision event while vectoring successive dep...

Narrative:

[City] was IFR and final west was split off and busy. Center called and apreq'ed air carrier Y stopped at an altitude above air carrier X while continuing to fly the ground track of the arrival. The aircraft were an exact tie at the entry fix to my airspace. To split the aircraft up; so both could descend; I turned air carrier X; the slower aircraft; to heading 060 with a descent to 4;000 ft and slowed them to 220 KTS. I then turned air carrier Y to heading 040 and used altitude separation until they were established on diverging courses; then descended him to 4;000 ft. I switched the heavy to final west who turned air carrier Y to heading 030 and slowed them to 210 knots. I observed this and when I had more than 5 miles separation I turned air carrier X to heading 340 to pass well behind the heavy. I observed air carrier X pass behind air carrier Y's wake turbulence with more than 5 miles separation. I was later informed air carrier X called to complain and ask why they had been vectored in the wake of a heavy. [I] recommend center review the LOA between center and TRACON and comply with the LOA; especially during peak traffic times.

Original NASA ASRS Text

Title: TRACON Controller described a pilot filed NMAC event while vectoring successive departure aircraft; one aircraft vectored behind a heavy B747; reporter claiming appropriate separation existed.

Narrative: [City] was IFR and Final West was split off and busy. Center called and APREQ'ed Air Carrier Y stopped at an altitude above Air Carrier X while continuing to fly the ground track of the arrival. The aircraft were an exact tie at the entry fix to my airspace. To split the aircraft up; so both could descend; I turned Air Carrier X; the slower aircraft; to heading 060 with a descent to 4;000 FT and slowed them to 220 KTS. I then turned Air Carrier Y to heading 040 and used altitude separation until they were established on diverging courses; then descended him to 4;000 FT. I switched the heavy to final West who turned Air Carrier Y to heading 030 and slowed them to 210 knots. I observed this and when I had more than 5 miles separation I turned Air Carrier X to heading 340 to pass well behind the heavy. I observed Air Carrier X pass behind Air Carrier Y's wake turbulence with more than 5 miles separation. I was later informed Air Carrier X called to complain and ask why they had been vectored in the wake of a heavy. [I] recommend Center review the LOA between Center and TRACON and comply with the LOA; especially during peak traffic times.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1097637
Time
Date	201306
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	SF 340B
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Published Material / Policy

TRACON controller described a pilot filed near midair collision event while vectoring successive departure aircraft; one aircraft vectored behind a heavy B747; reporter claiming appropriate separation existed.