Narrative:

Flying the el nido five star into sjc inbound to gilro we were level at 10;000 MSL. Approximately 5 miles from gilro we were told to descend to 8;000 ft. I promptly read back the 8;000 ft descent instruction. During this time the captain decided that that a descent to 8;000 ft would put us into conflict with traffic on the TCAS display; so he told me (once I unkeyed the mic) to tell ATC we needed to maintain 10;000 for a few more seconds until the collision threat passed. I looked at the TCAS display; it showed two traffic symbols close to us; below us; and climbing. I then told ATC that we needed to maintain 10;000 due to traffic until they were past us. ATC then said that they were planning to bring us under the traffic but to now maintain 10;000. I read back the maintain 10;000. ATC then started to say something to the traffic below us; but it was drowned out by a quick 'traffic' audio message; followed by a RA to 'climb.' the captain disconnected the autopilot and flew the RA while I monitored to ensure he complied with the RA. During this time ATC continued to talk to the other traffic; I was too busy to notice what ATC said to that traffic. I waited for the controller to stop transmitting; and then I reported the RA climb to ATC. We had climbed 800 ft during the RA event. On our TCAS display; the conflicting RA traffic showed they stayed at least 500 ft below our relative altitude the entire time during the event. During this event I never saw any traffic visually. I do not know if the captain saw the traffic visually or not during the event. Neither of us believes a loss of separation occurred in this case; but I am filing this report just in case I am mistaken.the critical factor was time in this event. The captain believed the initial ATC instruction put us at a collision risk. It would have been quicker to key the mic himself; rather than tell me (the pilot not flying); then have me relay to ATC. I believe ATC did issue a potential collision course that the captain caught; but insufficient time existed to stop the other aircraft from climbing enough to cause an RA. Rather than issuing a new clearance to maintain 10;000 ft; then issuing a new instruction to the other traffic; the other traffic should have been told to stop climb first. ATC should also anticipate the natural reluctance to descend into climbing traffic; and anticipate refusal or delay in an ATC instruction (such as a descent) may occur.

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Original NASA ASRS Text

Title: DA2000 First Officer reports declining a descent clearance from ATC at the Captains request; due to traffic on the TCAS display. This results in a TCAS TA then RA to climb; to which the crew responds.

Narrative: Flying the El Nido Five star into SJC inbound to GILRO we were level at 10;000 MSL. Approximately 5 miles from GILRO we were told to descend to 8;000 FT. I promptly read back the 8;000 FT descent instruction. During this time the Captain decided that that a descent to 8;000 FT would put us into conflict with traffic on the TCAS display; so he told me (once I unkeyed the mic) to tell ATC we needed to maintain 10;000 for a few more seconds until the collision threat passed. I looked at the TCAS display; it showed two traffic symbols close to us; below us; and climbing. I then told ATC that we needed to maintain 10;000 due to traffic until they were past us. ATC then said that they were planning to bring us under the traffic but to now maintain 10;000. I read back the maintain 10;000. ATC then started to say something to the traffic below us; but it was drowned out by a quick 'traffic' audio message; followed by a RA to 'climb.' The Captain disconnected the autopilot and flew the RA while I monitored to ensure he complied with the RA. During this time ATC continued to talk to the other traffic; I was too busy to notice what ATC said to that traffic. I waited for the controller to stop transmitting; and then I reported the RA climb to ATC. We had climbed 800 FT during the RA event. On our TCAS display; the conflicting RA traffic showed they stayed at least 500 FT below our relative altitude the entire time during the event. During this event I never saw any traffic visually. I do not know if the Captain saw the traffic visually or not during the event. Neither of us believes a loss of separation occurred in this case; but I am filing this report just in case I am mistaken.The critical factor was time in this event. The Captain believed the initial ATC instruction put us at a collision risk. It would have been quicker to key the mic himself; rather than tell me (the pilot not flying); then have me relay to ATC. I believe ATC did issue a potential collision course that the Captain caught; but insufficient time existed to stop the other aircraft from climbing enough to cause an RA. Rather than issuing a new clearance to maintain 10;000 FT; then issuing a new instruction to the other traffic; the other traffic should have been told to stop climb first. ATC should also anticipate the natural reluctance to descend into climbing traffic; and anticipate refusal or delay in an ATC instruction (such as a descent) may occur.

Data retrieved from NASA's ASRS site as of April 2012 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.