Cpr X same altitude assigned. Had less than standard separation from cpr Y. System error.

Attributes
ACN	274177
Time
Date	199406
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : phl
State Reference	PA
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl
Operator	general aviation : corporate
Make Model Name	Challenger CL601
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Challenger CL601
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : departure
Qualification	controller : radar
Experience	controller radar : 11
ASRS Report	274177
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 600
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Cpr X a CL61 departed runway 17 at phl. I turned the aircraft to a 120 degree heading and issued a climb to 10000 ft with a 250 K speed restr. Shortly thereafter issued 230 KTS for in-trail spacing. X needed to be in-trail to another CL61 Y already at 10000 ft that had departed ilg and was rted over the ditcn intersection for ZNY. I noticed that the speed restr would not be enough for the required spacing so I turned X to a 180 degree heading and pointed him out to the south arrival (sa) sector climbing to 9000 ft. I next turned X to a 040 degree heading and asked for a good rate to 9000 ft. The pilot read back the 040 degree heading and said 'we'll hurry up to 9000 ft.' at this point I was expecting X to level at 9000 ft. I told him about the traffic overhead at 10000 ft. He responded that he was at 9400 ft for 10000 ft. I issued 9000 ft to X and the pilot complied. On the flight progress strip I had written 90, which indicated that 9000 ft was issued to the pilot. I do not recall when I wrote this but I remember thinking all along that I had issued 9000 ft initially.

Original NASA ASRS Text

Title: CPR X SAME ALT ASSIGNED. HAD LTSS FROM CPR Y. SYS ERROR.

Narrative: CPR X A CL61 DEPARTED RWY 17 AT PHL. I TURNED THE ACFT TO A 120 DEG HDG AND ISSUED A CLB TO 10000 FT WITH A 250 K SPD RESTR. SHORTLY THEREAFTER ISSUED 230 KTS FOR IN-TRAIL SPACING. X NEEDED TO BE IN-TRAIL TO ANOTHER CL61 Y ALREADY AT 10000 FT THAT HAD DEPARTED ILG AND WAS RTED OVER THE DITCN INTXN FOR ZNY. I NOTICED THAT THE SPD RESTR WOULD NOT BE ENOUGH FOR THE REQUIRED SPACING SO I TURNED X TO A 180 DEG HDG AND POINTED HIM OUT TO THE S ARR (SA) SECTOR CLBING TO 9000 FT. I NEXT TURNED X TO A 040 DEG HDG AND ASKED FOR A GOOD RATE TO 9000 FT. THE PLT READ BACK THE 040 DEG HDG AND SAID 'WE'LL HURRY UP TO 9000 FT.' AT THIS POINT I WAS EXPECTING X TO LEVEL AT 9000 FT. I TOLD HIM ABOUT THE TFC OVERHEAD AT 10000 FT. HE RESPONDED THAT HE WAS AT 9400 FT FOR 10000 FT. I ISSUED 9000 FT TO X AND THE PLT COMPLIED. ON THE FLT PROGRESS STRIP I HAD WRITTEN 90, WHICH INDICATED THAT 9000 FT WAS ISSUED TO THE PLT. I DO NOT RECALL WHEN I WROTE THIS BUT I REMEMBER THINKING ALL ALONG THAT I HAD ISSUED 9000 FT INITIALLY.

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.