Aircraft descended through altitude of another aircraft.

Attributes
ACN	106985
Time
Date	198903
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : csn
State Reference	VA
Altitude	msl bound lower : 19800 msl bound upper : 20000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc tracon : dca
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 5 controller radar : 4
ASRS Report	106985
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : developmental
Events
Anomaly	non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance
Consequence	faa : investigated
Miss Distance	horizontal : 10800 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Inter Facility Coordination Failure Operational Error

Narrative:

Working csn sector with r-side trnee and an light transport landing bwi. Because of crossing traffic at FL200, light transport was descending to FL210. After crossing traffic, light transport was descended to FL190 and we attempted a handoff to ZDC approach. Approach controller said, 'I take it he's at FL210?' trnee said, 'yeah, I had to stop him for FL200 traffic.' approach controller accepted radar on light transport. At that time I was telling my trnee that the coordination was not correct, because light transport was descending to FL190. Trnee then saw limited data tag on our boundary at FL200. I called approach and told him our aircraft was descending to FL190 and I was turning him left. I turned light transport 40 degrees to the left, then turned him to a 360 degree heading and called the traffic. Light transport saw traffic and I cleared him on course. At no time did we receive a pointout on the aircraft at FL200 on our boundary (medium large transport). I feel that if we had gotten a pointout on medium large transport at the appropriate time, this operational error would not have occurred.

Original NASA ASRS Text

Title: ACFT DESCENDED THROUGH ALT OF ANOTHER ACFT.

Narrative: WORKING CSN SECTOR WITH R-SIDE TRNEE AND AN LTT LNDG BWI. BECAUSE OF XING TFC AT FL200, LTT WAS DSNDING TO FL210. AFTER XING TFC, LTT WAS DSNDED TO FL190 AND WE ATTEMPTED A HDOF TO ZDC APCH. APCH CTLR SAID, 'I TAKE IT HE'S AT FL210?' TRNEE SAID, 'YEAH, I HAD TO STOP HIM FOR FL200 TFC.' APCH CTLR ACCEPTED RADAR ON LTT. AT THAT TIME I WAS TELLING MY TRNEE THAT THE COORD WAS NOT CORRECT, BECAUSE LTT WAS DSNDING TO FL190. TRNEE THEN SAW LIMITED DATA TAG ON OUR BOUNDARY AT FL200. I CALLED APCH AND TOLD HIM OUR ACFT WAS DSNDING TO FL190 AND I WAS TURNING HIM LEFT. I TURNED LTT 40 DEGS TO THE LEFT, THEN TURNED HIM TO A 360 DEG HDG AND CALLED THE TFC. LTT SAW TFC AND I CLRED HIM ON COURSE. AT NO TIME DID WE RECEIVE A POINTOUT ON THE ACFT AT FL200 ON OUR BOUNDARY (MLG). I FEEL THAT IF WE HAD GOTTEN A POINTOUT ON MLG AT THE APPROPRIATE TIME, THIS OPERROR WOULD NOT HAVE OCCURRED.

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.