Report of a potential loss of separation when an overtaking air carrier DC9 in trail to a slower air carrier B757 mistakenly takes the frequency change to gso approach intended for the B757. Reporter claims center separation not lost before aircraft entered approach airspace.

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Attributes
ACN	383494
Time
Date	199710
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : gso
State Reference	NC
Altitude	msl bound lower : 11000 msl bound upper : 11000
Environment
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : ztl tower : mlb
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar pilot : student
Experience	controller radar : 16 flight time total : 10
ASRS Report	383494
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Miss Distance	horizontal : 30000 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

B757 was in front, inbound gso on the spa transition of the BROOK2 STAR. The DC9 was inbound gso on the gzg transition of the BROOK2. The DC9 was overtaking. I turned the B757 in short to stay in front. The B757 asked if I wanted him to slow down per the STAR. I said negative. I switched the B757 to gso approach. The reply was '124.35, see ya.' it took a second to register but the voice didn't sound right. Sure enough it was the DC9 that had answered. I didn't think abc sounded close enough to worry about it. The DC9 didn't worry about using his call sign for a frequency change. This is a very common problem. The DC9 was overtaking the B757 by 100 KTS. When I tried to slow him down he wasn't there. Fortunately both aircraft entered gso airspace before my separation was lost. Phraseology/radio technique is becoming a major problem. Even something as simple as using your call sign on a frequency change can be important.

Original NASA ASRS Text

Title: RPT OF A POTENTIAL LOSS OF SEPARATION WHEN AN OVERTAKING ACR DC9 IN TRAIL TO A SLOWER ACR B757 MISTAKENLY TAKES THE FREQ CHANGE TO GSO APCH INTENDED FOR THE B757. RPTR CLAIMS CTR SEPARATION NOT LOST BEFORE ACFT ENTERED APCH AIRSPACE.

Narrative: B757 WAS IN FRONT, INBOUND GSO ON THE SPA TRANSITION OF THE BROOK2 STAR. THE DC9 WAS INBOUND GSO ON THE GZG TRANSITION OF THE BROOK2. THE DC9 WAS OVERTAKING. I TURNED THE B757 IN SHORT TO STAY IN FRONT. THE B757 ASKED IF I WANTED HIM TO SLOW DOWN PER THE STAR. I SAID NEGATIVE. I SWITCHED THE B757 TO GSO APCH. THE REPLY WAS '124.35, SEE YA.' IT TOOK A SECOND TO REGISTER BUT THE VOICE DIDN'T SOUND RIGHT. SURE ENOUGH IT WAS THE DC9 THAT HAD ANSWERED. I DIDN'T THINK ABC SOUNDED CLOSE ENOUGH TO WORRY ABOUT IT. THE DC9 DIDN'T WORRY ABOUT USING HIS CALL SIGN FOR A FREQ CHANGE. THIS IS A VERY COMMON PROB. THE DC9 WAS OVERTAKING THE B757 BY 100 KTS. WHEN I TRIED TO SLOW HIM DOWN HE WASN'T THERE. FORTUNATELY BOTH ACFT ENTERED GSO AIRSPACE BEFORE MY SEPARATION WAS LOST. PHRASEOLOGY/RADIO TECHNIQUE IS BECOMING A MAJOR PROB. EVEN SOMETHING AS SIMPLE AS USING YOUR CALL SIGN ON A FREQ CHANGE CAN BE IMPORTANT.

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.