Air carrier X TCASII TA RA evasive action descend had less than standard separation from air carrier...

Attributes
ACN	289739
Time
Date	199411
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : stl
State Reference	MO
Altitude	msl bound lower : 27600 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zkc artcc : zny
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : atp
Experience	flight time last 90 days : 190 flight time total : 9000 flight time type : 1300
ASRS Report	289739
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : published procedure non adherence : required legal separation other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	faa : investigated
Miss Distance	horizontal : 5000 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X on J110 65 mi west of stl at FL280. Air carrier X received a TCASII TA. Within 10 seconds we received a TCASII RA with a verbal command to 'descend.' the captain took immediate action and started a descent. Within 3 seconds, TCASII gave another verbal command to 'descend now.' the ATC controller then responded with 'X, turn right heading 360 degrees.' the captain started the turn toward 360 degrees. The first officer acknowledged the ATC instructions and advised the ATC controller we were descending per a TCASII RA. The controller responded with, 'don't descend,' followed with 'tighten up your turn.' I observed the other aircraft pass off the left of our aircraft within 400 ft of our assigned altitude. ATC then assigned us FL270. The other aircraft was air carrier Y. The first officer then stated to ATC the desire to report an near midair collision and that all information on the incident is requested.

Original NASA ASRS Text

Title: ACR X TCASII TA RA EVASIVE ACTION DSND HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: ACR X ON J110 65 MI W OF STL AT FL280. ACR X RECEIVED A TCASII TA. WITHIN 10 SECONDS WE RECEIVED A TCASII RA WITH A VERBAL COMMAND TO 'DSND.' THE CAPT TOOK IMMEDIATE ACTION AND STARTED A DSCNT. WITHIN 3 SECONDS, TCASII GAVE ANOTHER VERBAL COMMAND TO 'DSND NOW.' THE ATC CTLR THEN RESPONDED WITH 'X, TURN R HDG 360 DEGS.' THE CAPT STARTED THE TURN TOWARD 360 DEGS. THE FO ACKNOWLEDGED THE ATC INSTRUCTIONS AND ADVISED THE ATC CTLR WE WERE DSNDING PER A TCASII RA. THE CTLR RESPONDED WITH, 'DON'T DSND,' FOLLOWED WITH 'TIGHTEN UP YOUR TURN.' I OBSERVED THE OTHER ACFT PASS OFF THE L OF OUR ACFT WITHIN 400 FT OF OUR ASSIGNED ALT. ATC THEN ASSIGNED US FL270. THE OTHER ACFT WAS ACR Y. THE FO THEN STATED TO ATC THE DESIRE TO RPT AN NMAC AND THAT ALL INFO ON THE INCIDENT IS REQUESTED.

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.

Air carrier X TCASII TA RA evasive action descend had less than standard separation from air carrier Y. System error.