<< >> NASA ASRS Report 621365, June 2004

Pvd controller experienced operational error at 7000 ft with 2 GA aircraft. Wrong aircraft call sign was used, resulting in the conflicting aircraft accepting a frequency change.

Attributes
ACN	621365
Time
Date	200406
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : tmu.vor
State Reference	CT
Altitude	msl single value : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : pvd.tracon
Operator	general aviation : personal
Make Model Name	Bonanza 36
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : pvd.tracon
Operator	general aviation : personal
Make Model Name	Cessna 310/T310C
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller military : 9 controller radar : 7
ASRS Report	621365
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert
Resolutory Action	controller : issued new clearance
Consequence	faa : investigated
Miss Distance	vertical : 0
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

At approximately XA32, I received an aural alarm on 2 converging aircraft at 7000 ft, 8 mi southwest of tmu VOR. I immediately attempted to turn aircraft #2 with no reply. I then immediately turned aircraft #1 away from aircraft #2. I continued to try to issue control instructions to aircraft #2. But after reviewing the audio and video recording, I learned that aircraft #2 took a frequency change for another aircraft. I did not realize that this had happened because I was not yet in contact with aircraft #2. I had switched aircraft #3 to an adjacent controller using only aircraft #2 initially, and did not realize that even though he had not checked in with me, he took the frequency change for aircraft #3. I do not think that not having contact was the cause of the loss of separation. It may have reduced the severity to have contact with both aircraft, but I believe that loss of separation was inevitable.

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Original NASA ASRS Text

Title: PVD CTLR EXPERIENCED OPERROR AT 7000 FT WITH 2 GA ACFT. WRONG ACFT CALL SIGN WAS USED, RESULTING IN THE CONFLICTING ACFT ACCEPTING A FREQ CHANGE.

Narrative: AT APPROX XA32, I RECEIVED AN AURAL ALARM ON 2 CONVERGING ACFT AT 7000 FT, 8 MI SW OF TMU VOR. I IMMEDIATELY ATTEMPTED TO TURN ACFT #2 WITH NO REPLY. I THEN IMMEDIATELY TURNED ACFT #1 AWAY FROM ACFT #2. I CONTINUED TO TRY TO ISSUE CTL INSTRUCTIONS TO ACFT #2. BUT AFTER REVIEWING THE AUDIO AND VIDEO RECORDING, I LEARNED THAT ACFT #2 TOOK A FREQ CHANGE FOR ANOTHER ACFT. I DID NOT REALIZE THAT THIS HAD HAPPENED BECAUSE I WAS NOT YET IN CONTACT WITH ACFT #2. I HAD SWITCHED ACFT #3 TO AN ADJACENT CTLR USING ONLY ACFT #2 INITIALLY, AND DID NOT REALIZE THAT EVEN THOUGH HE HAD NOT CHKED IN WITH ME, HE TOOK THE FREQ CHANGE FOR ACFT #3. I DO NOT THINK THAT NOT HAVING CONTACT WAS THE CAUSE OF THE LOSS OF SEPARATION. IT MAY HAVE REDUCED THE SEVERITY TO HAVE CONTACT WITH BOTH ACFT, BUT I BELIEVE THAT LOSS OF SEPARATION WAS INEVITABLE.

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.