<< >> NASA ASRS Report 338246, June 1996

ARTCC radar controller climbed an MD80 to same altitude as another MD80 and had less than standard separation due to speed differential.

Attributes
ACN	338246
Time
Date	199606
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : iiu
State Reference	KY
Altitude	msl bound lower : 34500 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	338246
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 21000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

MD80 (X) was swbound at FL350. MD80 (Y) was southeast of MD80 (X) about 6 mi behind at FL330 requesting FL350. I had the controller working MD80 (Y) turn him 30 degrees right and slow him down as much as feasible. When MD80 (Y) was switched to my frequency I told him to reduce speed as much as feasible and climb to FL350. When I looked at the speeds a couple of updates later, MD80 (Y) had increased 20 KTS due to the jetstream. Shortly thereafter I turned MD80 (Y) to the left and MD80 (X) to the right and regained my separation.

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Original NASA ASRS Text

Title: ARTCC RADAR CTLR CLBED AN MD80 TO SAME ALT AS ANOTHER MD80 AND HAD LTSS DUE TO SPD DIFFERENTIAL.

Narrative: MD80 (X) WAS SWBOUND AT FL350. MD80 (Y) WAS SE OF MD80 (X) ABOUT 6 MI BEHIND AT FL330 REQUESTING FL350. I HAD THE CTLR WORKING MD80 (Y) TURN HIM 30 DEGS R AND SLOW HIM DOWN AS MUCH AS FEASIBLE. WHEN MD80 (Y) WAS SWITCHED TO MY FREQ I TOLD HIM TO REDUCE SPD AS MUCH AS FEASIBLE AND CLB TO FL350. WHEN I LOOKED AT THE SPDS A COUPLE OF UPDATES LATER, MD80 (Y) HAD INCREASED 20 KTS DUE TO THE JETSTREAM. SHORTLY THEREAFTER I TURNED MD80 (Y) TO THE L AND MD80 (X) TO THE R AND REGAINED MY SEPARATION.

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.