Loss of separation occurred when second aircraft overtook the first aircraft.

Attributes
ACN	116393
Time
Date	198907
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ont
State Reference	CA
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ont tower : hou
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	arrival other
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	arrival other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	116393
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly
Independent Detector	other controllera other flight crewa
Resolutory Action	other
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Aircraft a was proceeding nwbound at 8000'. Aircraft B was proceeding wbound descending from 14,000' to 6000' and reducing airspeed to 170 KTS. Aircraft a was turned wbound behind aircraft B. The overtake was such that separation was lost. The problem was discovered by both pilot (pointing out traffic) and by the controller (realizing the situation). A factor contributing to this situation is high speed aircraft are forced to descend to 8000' when still 100 miles from their destination.

Original NASA ASRS Text

Title: LOSS OF SEPARATION OCCURRED WHEN SECOND ACFT OVERTOOK THE FIRST ACFT.

Narrative: ACFT A WAS PROCEEDING NWBOUND AT 8000'. ACFT B WAS PROCEEDING WBOUND DESCENDING FROM 14,000' TO 6000' AND REDUCING AIRSPEED TO 170 KTS. ACFT A WAS TURNED WBOUND BEHIND ACFT B. THE OVERTAKE WAS SUCH THAT SEPARATION WAS LOST. THE PROBLEM WAS DISCOVERED BY BOTH PLT (POINTING OUT TFC) AND BY THE CTLR (REALIZING THE SITUATION). A FACTOR CONTRIBUTING TO THIS SITUATION IS HIGH SPEED ACFT ARE FORCED TO DSND TO 8000' WHEN STILL 100 MILES FROM THEIR DEST.

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.