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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.