ZID controller lost separation during overtake situation at 16000 ft.

Attributes
ACN	596451
Time
Date	200310
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : ood.vortac
State Reference	NJ
Altitude	msl single value : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : ood
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	A310
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller military : 3.5 controller radar : 14 controller time certified in position1 : 10
ASRS Report	596451
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert other controllera
Resolutory Action	none taken : insufficient time
Consequence	faa : investigated
Miss Distance	horizontal : 26400 vertical : 400
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Took handoff on aircraft #1 from phl approach climbing to 13000 ft. Took handoff on aircraft #2 from phl approach approximately 8 mi in-trail also climbing to 12000 ft. I climbed aircraft #1 to 16000 ft. Aircraft #1 had crossing traffic at 17000 ft. I then climbed aircraft #2 to 16000 ft. Both aircraft were comparable in type and performance and had filed speeds within 10 KTS. I proceeded to issue other control instructions to other aircraft. A VFR aircraft called wanting to pick up IFR. I idented the aircraft and put him on the appropriate frequency. I looked back to climb aircraft #1. I realized aircraft #2 was rapidly overtaking aircraft #1. I climbed aircraft #1 to 17000 ft and slowed aircraft #2 to 250 KTS. Aircraft #2 was approximately 100 KTS faster than aircraft #1. Neither pilot stated they were flying at a speed other than normal filed speed. At the time I issued the control instructions to climb and slow, the aircraft were separated by approximately 5.5 mi.

Original NASA ASRS Text

Title: ZID CTLR LOST SEPARATION DURING OVERTAKE SIT AT 16000 FT.

Narrative: TOOK HDOF ON ACFT #1 FROM PHL APCH CLBING TO 13000 FT. TOOK HDOF ON ACFT #2 FROM PHL APCH APPROX 8 MI IN-TRAIL ALSO CLBING TO 12000 FT. I CLBED ACFT #1 TO 16000 FT. ACFT #1 HAD XING TFC AT 17000 FT. I THEN CLBED ACFT #2 TO 16000 FT. BOTH ACFT WERE COMPARABLE IN TYPE AND PERFORMANCE AND HAD FILED SPDS WITHIN 10 KTS. I PROCEEDED TO ISSUE OTHER CTL INSTRUCTIONS TO OTHER ACFT. A VFR ACFT CALLED WANTING TO PICK UP IFR. I IDENTED THE ACFT AND PUT HIM ON THE APPROPRIATE FREQ. I LOOKED BACK TO CLB ACFT #1. I REALIZED ACFT #2 WAS RAPIDLY OVERTAKING ACFT #1. I CLBED ACFT #1 TO 17000 FT AND SLOWED ACFT #2 TO 250 KTS. ACFT #2 WAS APPROX 100 KTS FASTER THAN ACFT #1. NEITHER PLT STATED THEY WERE FLYING AT A SPD OTHER THAN NORMAL FILED SPD. AT THE TIME I ISSUED THE CTL INSTRUCTIONS TO CLB AND SLOW, THE ACFT WERE SEPARATED BY APPROX 5.5 MI.

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.