Less than standard separation between 2 GA aircraft. Operational error.

Attributes
ACN	93089
Time
Date	198808
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sbv
State Reference	VA
Altitude	msl bound lower : 7000 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Navigation In Use	other vortac
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 2 controller radar : 20
ASRS Report	93089
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : insufficient time other
Consequence	faa : investigated
Miss Distance	horizontal : 18000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error Intra Facility Coordination Failure

Narrative:

Small aircraft X, ckb to rdu, came on frequency at 9000' requesting direct to rdu. Later the pilot said he wasn't receiving rdu and asked if his heading was good. I assured him his heading appeared to be taking him to rdu. Small transport Y, clt to ric, came on the frequency later at 7000'. After observing that the tracks of these 2 aircraft would cross at a point south of sbv VORTAC, I decided I could descend X to 6000' and stay out of the protected airspace for Y, who was at 7000'. I later noticed the 2 aircraft were going to end up with less than standard separation. I turned X to heading 090 degrees and turned Y to a heading of 330 degrees. With these turns the aircraft came no closer than 3 mi to each other while they were at the same altitude. When the 2 aircraft had sufficient sep I cleared X direct to rdu. The pilot said he was not receiving rdu. I put him on a heading for rdu. I then got the information that rdu was off the air for scheduled maintenance. I believe aircraft X drifted west of a direct course to rdu because he wasn't receiving the VORTAC. If I had the information about the rdu VORTAC outage I would have had X on a heading and he probably would not have violated the protected airspace of Y.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN 2 GA ACFT. OPERATIONAL ERROR.

Narrative: SMA X, CKB TO RDU, CAME ON FREQ AT 9000' REQUESTING DIRECT TO RDU. LATER THE PLT SAID HE WASN'T RECEIVING RDU AND ASKED IF HIS HDG WAS GOOD. I ASSURED HIM HIS HDG APPEARED TO BE TAKING HIM TO RDU. SMT Y, CLT TO RIC, CAME ON THE FREQ LATER AT 7000'. AFTER OBSERVING THAT THE TRACKS OF THESE 2 ACFT WOULD CROSS AT A POINT S OF SBV VORTAC, I DECIDED I COULD DSND X TO 6000' AND STAY OUT OF THE PROTECTED AIRSPACE FOR Y, WHO WAS AT 7000'. I LATER NOTICED THE 2 ACFT WERE GOING TO END UP WITH LTSS. I TURNED X TO HDG 090 DEGS AND TURNED Y TO A HDG OF 330 DEGS. WITH THESE TURNS THE ACFT CAME NO CLOSER THAN 3 MI TO EACH OTHER WHILE THEY WERE AT THE SAME ALT. WHEN THE 2 ACFT HAD SUFFICIENT SEP I CLRED X DIRECT TO RDU. THE PLT SAID HE WAS NOT RECEIVING RDU. I PUT HIM ON A HDG FOR RDU. I THEN GOT THE INFO THAT RDU WAS OFF THE AIR FOR SCHEDULED MAINT. I BELIEVE ACFT X DRIFTED W OF A DIRECT COURSE TO RDU BECAUSE HE WASN'T RECEIVING THE VORTAC. IF I HAD THE INFO ABOUT THE RDU VORTAC OUTAGE I WOULD HAVE HAD X ON A HDG AND HE PROBABLY WOULD NOT HAVE VIOLATED THE PROTECTED AIRSPACE OF Y.

Data retrieved from NASA's ASRS site as of August 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.