B757 flight crew executed a TCASII RA climb when, apparently, an MD88 descends 500 ft below assigned altitude. ARTCC controller actions could not stop loss of separation.

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Attributes
ACN	405904
Time
Date	199806
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hvq
State Reference	WV
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
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 : 200 flight time total : 7000 flight time type : 2500
ASRS Report	405904
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 225 flight time total : 21000 flight time type : 3600
ASRS Report	405913
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 750
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While in cruise heading east (090 degrees) on the J-8 airway, we had a traffic conflict (TCASII RA): had an aural TA. Looked down at scope and saw traffic at same altitude approximately 12 O'clock position either 10 or 20 mi. ATC gave us a turn right to 160 degrees. He did not say immediately or sound stressful in his voice. We turned right immediately using autoplt. Right after starting turn we received a TCASII RA commanding a climb. Turned off autoplt and climbed approximately 250-300 ft. When we started our turn we both (and jump seater) saw the traffic. We had the aircraft in sight while we were climbing and turning. The 3 of us estimated horizontal distance of 1-2 mi. The other aircraft told ATC that they had descended 400-500 ft, so our vertical miss was about 750 ft. When traffic had passed and TCASII commanded 'clear', we went back to FL290. We told ATC of conflict and that we climbed and asked what happened. He never gave us a clear answer and cleared us back on course. Supplemental information from acn 405913: we climbed approximately 250 ft in a right climbing turn. Air carrier Y reported he descended 500 ft but I don't think he initiated a turn. Both of us were at FL290.

Original NASA ASRS Text

Title: B757 FLC EXECUTED A TCASII RA CLB WHEN, APPARENTLY, AN MD88 DSNDS 500 FT BELOW ASSIGNED ALT. ARTCC CTLR ACTIONS COULD NOT STOP LOSS OF SEPARATION.

Narrative: WHILE IN CRUISE HEADING E (090 DEGS) ON THE J-8 AIRWAY, WE HAD A TFC CONFLICT (TCASII RA): HAD AN AURAL TA. LOOKED DOWN AT SCOPE AND SAW TFC AT SAME ALT APPROX 12 O'CLOCK POS EITHER 10 OR 20 MI. ATC GAVE US A TURN R TO 160 DEGS. HE DID NOT SAY IMMEDIATELY OR SOUND STRESSFUL IN HIS VOICE. WE TURNED R IMMEDIATELY USING AUTOPLT. RIGHT AFTER STARTING TURN WE RECEIVED A TCASII RA COMMANDING A CLB. TURNED OFF AUTOPLT AND CLBED APPROX 250-300 FT. WHEN WE STARTED OUR TURN WE BOTH (AND JUMP SEATER) SAW THE TFC. WE HAD THE ACFT IN SIGHT WHILE WE WERE CLBING AND TURNING. THE 3 OF US ESTIMATED HORIZ DISTANCE OF 1-2 MI. THE OTHER ACFT TOLD ATC THAT THEY HAD DSNDED 400-500 FT, SO OUR VERT MISS WAS ABOUT 750 FT. WHEN TFC HAD PASSED AND TCASII COMMANDED 'CLR', WE WENT BACK TO FL290. WE TOLD ATC OF CONFLICT AND THAT WE CLBED AND ASKED WHAT HAPPENED. HE NEVER GAVE US A CLR ANSWER AND CLRED US BACK ON COURSE. SUPPLEMENTAL INFO FROM ACN 405913: WE CLBED APPROX 250 FT IN A R CLBING TURN. ACR Y RPTED HE DSNDED 500 FT BUT I DON'T THINK HE INITIATED A TURN. BOTH OF US WERE AT FL290.

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.