Air carrier at cruise receives TCASII TA then RA. Responds with descent.

Attributes
ACN	206316
Time
Date	199203
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ccv
State Reference	VA
Altitude	msl bound lower : 22000 msl bound upper : 24000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 90 flight time total : 5500 flight time type : 240
ASRS Report	206316
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 2300 flight time type : 580
ASRS Report	206178
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 18000 vertical : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

With no warning from ATC. We received a TA from our onboard TCASII, shortly followed by a descend command. We simultaneously informed center we were descending from our assigned altitude of FL240, and departed for a lower altitude. The conflict was resolved as we reached FL235. After climbing back to FL240, ATC informed us that the conflicting traffic was a corp jet descending at a rate of 3000 FPM from FL290 to FL250 on a head-on direction. The controller said the corp jet was to pass 3 mi west of our position. Due to the 1000 ft and 3 mi separation, the controller felt it unnecessary to advise us of the merging traffic (jet was told to expedite his descent). Controllers need to incorporate into their procedures actions which will not set off TCASII problems. If ATC descends aircraft with head on courses at expeditious rates, as was the case here, they're going to have aircraft breaking out of the pattern all over the place. Recommend 30 degree turns away from other traffic for 'expediting' climbs or dscnts when newly assigned altitudes are within 1000 ft of other aircraft. Supplemental information from acn 206178: the center controller told us to disregard the TCASII and maintain our altitude. We told the controller we couldn't do that. He then told us not to descend below FL220 and traffic was not a factor. We were concerned about the fact of a controller telling us to ignore a TCASII RA especially when we were IMC and could not see the conflicting aircraft.

Original NASA ASRS Text

Title: ACR AT CRUISE RECEIVES TCASII TA THEN RA. RESPONDS WITH DSCNT.

Narrative: WITH NO WARNING FROM ATC. WE RECEIVED A TA FROM OUR ONBOARD TCASII, SHORTLY FOLLOWED BY A DSND COMMAND. WE SIMULTANEOUSLY INFORMED CTR WE WERE DSNDING FROM OUR ASSIGNED ALT OF FL240, AND DEPARTED FOR A LOWER ALT. THE CONFLICT WAS RESOLVED AS WE REACHED FL235. AFTER CLBING BACK TO FL240, ATC INFORMED US THAT THE CONFLICTING TFC WAS A CORP JET DSNDING AT A RATE OF 3000 FPM FROM FL290 TO FL250 ON A HEAD-ON DIRECTION. THE CTLR SAID THE CORP JET WAS TO PASS 3 MI W OF OUR POS. DUE TO THE 1000 FT AND 3 MI SEPARATION, THE CTLR FELT IT UNNECESSARY TO ADVISE US OF THE MERGING TFC (JET WAS TOLD TO EXPEDITE HIS DSCNT). CTLRS NEED TO INCORPORATE INTO THEIR PROCS ACTIONS WHICH WILL NOT SET OFF TCASII PROBLEMS. IF ATC DSNDS ACFT WITH HEAD ON COURSES AT EXPEDITIOUS RATES, AS WAS THE CASE HERE, THEY'RE GOING TO HAVE ACFT BREAKING OUT OF THE PATTERN ALL OVER THE PLACE. RECOMMEND 30 DEG TURNS AWAY FROM OTHER TFC FOR 'EXPEDITING' CLBS OR DSCNTS WHEN NEWLY ASSIGNED ALTS ARE WITHIN 1000 FT OF OTHER ACFT. SUPPLEMENTAL INFO FROM ACN 206178: THE CTR CTLR TOLD US TO DISREGARD THE TCASII AND MAINTAIN OUR ALT. WE TOLD THE CTLR WE COULDN'T DO THAT. HE THEN TOLD US NOT TO DSND BELOW FL220 AND TFC WAS NOT A FACTOR. WE WERE CONCERNED ABOUT THE FACT OF A CTLR TELLING US TO IGNORE A TCASII RA ESPECIALLY WHEN WE WERE IMC AND COULD NOT SEE THE CONFLICTING 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.