2 MD88 aircraft on vectors for approach landing in IMC both received and followed TCASII RA's. One aircraft climbed 800 ft and the other descended 200 ft.

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Attributes
ACN	365381
Time
Date	199703
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cvg
State Reference	OH
Altitude	msl bound lower : 4800 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cvg
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 other
Route In Use	enroute : on vectors
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 other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 130 flight time total : 11000 flight time type : 350
ASRS Report	365381
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 8000 flight time type : 400
ASRS Report	364929
Events
Anomaly	conflict : nmac non adherence : far non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	vertical : 100
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

On approach to runway 18L at cvg, base leg, 5000 ft MSL, 180 KTS, we received an RA on TCASII. TCASII directed 'descend, descend.' we immediately complied, being in IMC. TCASII then directed 'monitor vertical speed.' at approximately 4800 ft we were 'clear of conflict.' landed at cvg uneventfully. Captain of conflict aircraft advised us that he was 100 ft above us when he received and reacted to his RA. He was directed to climb by TCASII and then 'descend' due to a subsequent conflict at a higher altitude. All aircraft then returned to assigned altitudes and landed uneventfully. Due to TCASII a possible disaster was avoided. Recommendations: 1) improve ATC system. 2) reduce controller workload. 3) greater controller vigilance in IMC. 4) increase separation on approach in IMC. I believe main problem was due to controller misjudgement in vectoring aircraft.

Original NASA ASRS Text

Title: 2 MD88 ACFT ON VECTORS FOR APCH LNDG IN IMC BOTH RECEIVED AND FOLLOWED TCASII RA'S. ONE ACFT CLBED 800 FT AND THE OTHER DSNDED 200 FT.

Narrative: ON APCH TO RWY 18L AT CVG, BASE LEG, 5000 FT MSL, 180 KTS, WE RECEIVED AN RA ON TCASII. TCASII DIRECTED 'DSND, DSND.' WE IMMEDIATELY COMPLIED, BEING IN IMC. TCASII THEN DIRECTED 'MONITOR VERT SPD.' AT APPROX 4800 FT WE WERE 'CLR OF CONFLICT.' LANDED AT CVG UNEVENTFULLY. CAPT OF CONFLICT ACFT ADVISED US THAT HE WAS 100 FT ABOVE US WHEN HE RECEIVED AND REACTED TO HIS RA. HE WAS DIRECTED TO CLB BY TCASII AND THEN 'DSND' DUE TO A SUBSEQUENT CONFLICT AT A HIGHER ALT. ALL ACFT THEN RETURNED TO ASSIGNED ALTS AND LANDED UNEVENTFULLY. DUE TO TCASII A POSSIBLE DISASTER WAS AVOIDED. RECOMMENDATIONS: 1) IMPROVE ATC SYS. 2) REDUCE CTLR WORKLOAD. 3) GREATER CTLR VIGILANCE IN IMC. 4) INCREASE SEPARATION ON APCH IN IMC. I BELIEVE MAIN PROB WAS DUE TO CTLR MISJUDGEMENT IN VECTORING ACFT.

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.