Potential loss of separation between acrs and military transport. Operational deviation.

Attributes
ACN	92955
Time
Date	198808
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : tys
State Reference	TN
Altitude	msl bound lower : 26000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl tower : ogg
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Medium Large Transport
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 6500 flight time type : 1800
ASRS Report	92955
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 1000
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation Intra Facility Coordination Failure

Narrative:

We were cleared to 27000' by ZTL east of the knoxville VORTAC. We were given a frequency change just before the VORTAC. Just past the VORTAC and just about to level at 27000' we were given an immediate descent to 26000'. At the same time a military transport (Y) was crossing in front, from right to left, in a shallow left turn and descending. He was above us and about 1 1 /2 mi in front. I don't know what happened and center gave not a clue as to the situation. I believe 1000' sep was maintained--we went to 26000' quickly.

Original NASA ASRS Text

Title: POTENTIAL LOSS OF SEPARATION BETWEEN ACRS AND MIL TRANSPORT. OPERATIONAL DEVIATION.

Narrative: WE WERE CLRED TO 27000' BY ZTL E OF THE KNOXVILLE VORTAC. WE WERE GIVEN A FREQ CHANGE JUST BEFORE THE VORTAC. JUST PAST THE VORTAC AND JUST ABOUT TO LEVEL AT 27000' WE WERE GIVEN AN IMMEDIATE DSCNT TO 26000'. AT THE SAME TIME A MIL TRANSPORT (Y) WAS XING IN FRONT, FROM RIGHT TO LEFT, IN A SHALLOW LEFT TURN AND DSNDING. HE WAS ABOVE US AND ABOUT 1 1 /2 MI IN FRONT. I DON'T KNOW WHAT HAPPENED AND CENTER GAVE NOT A CLUE AS TO THE SITUATION. I BELIEVE 1000' SEP WAS MAINTAINED--WE WENT TO 26000' QUICKLY.

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.