Air carrier Y descent to occupied altitude had less than standard separation from air carrier X. Sys...

Attributes
ACN	251936
Time
Date	199309
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ott
State Reference	MD
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : bwi
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : direct enroute airway : bwi
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : radar
Experience	controller non radar : 4 controller radar : 1
ASRS Report	251936
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 25
ASRS Report	251821
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 8400 vertical : 800
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error Operational Deviation Intra Facility Coordination Failure

Narrative:

I was working D-53 and we had air carrier X propeller at 8000 ft. Air carrier Y was given belit at 11000 ft. I was told by supervisor that the r-side controller gave air carrier Y (that was a jet) to cross belit at 8000 ft. Just before air carrier Y was switched to baltimore approach, the incident occurred in baltimore approach's airspace. Supplemental information from acn 251821: I was told I was involved in an incident that resulted in less than standard separation 2 hours earlier. I had been working the sector for 2 plus hours. I believe actual loss of separation happened after I was relieved from duty. Callback conversation with reporter revealed the following information: reporter stated the aircraft were medium large transport and light transport. Separation was 1.4 mi and 800 ft and the loss of separation occurred in bwi approach control airspace. LOA with bwi requires ZDC to have propeller aircraft at 8000 ft and jet aircraft at 11000 ft. The reporter was giving a position relief briefing and inadvertently descended air carrier Y to wrong altitude.

Original NASA ASRS Text

Title: ACR Y DSCNT TO OCCUPIED ALT HAD LTSS FROM ACR X. SYS ERROR.

Narrative: I WAS WORKING D-53 AND WE HAD ACR X PROP AT 8000 FT. ACR Y WAS GIVEN BELIT AT 11000 FT. I WAS TOLD BY SUPVR THAT THE R-SIDE CTLR GAVE ACR Y (THAT WAS A JET) TO CROSS BELIT AT 8000 FT. JUST BEFORE ACR Y WAS SWITCHED TO BALTIMORE APCH, THE INCIDENT OCCURRED IN BALTIMORE APCH'S AIRSPACE. SUPPLEMENTAL INFO FROM ACN 251821: I WAS TOLD I WAS INVOLVED IN AN INCIDENT THAT RESULTED IN LTSS 2 HRS EARLIER. I HAD BEEN WORKING THE SECTOR FOR 2 PLUS HRS. I BELIEVE ACTUAL LOSS OF SEPARATION HAPPENED AFTER I WAS RELIEVED FROM DUTY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE ACFT WERE MLG AND LTT. SEPARATION WAS 1.4 MI AND 800 FT AND THE LOSS OF SEPARATION OCCURRED IN BWI APCH CTL AIRSPACE. LOA WITH BWI REQUIRES ZDC TO HAVE PROP ACFT AT 8000 FT AND JET ACFT AT 11000 FT. THE RPTR WAS GIVING A POS RELIEF BRIEFING AND INADVERTENTLY DSNDED ACR Y TO WRONG ALT.

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.

Air carrier Y descent to occupied altitude had less than standard separation from air carrier X. System error.