Large transport and medium large transport both have TCASII RA's and respond as indicated.

Attributes
ACN	309236
Time
Date	199507
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 11000 msl bound upper : 11500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
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
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 9500 flight time type : 3600
ASRS Report	309236
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 190 flight time total : 7500 flight time type : 950
ASRS Report	309088
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 : 1500 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error other

Narrative:

We were level at 11000 ft on our descent into sfo, on a radar vector when we got a TCASII RA to climb. We climbed immediately and at 11500 ft we got a 'clear of conflict.' in the meantime we sighted the other aircraft about 1:30 O'clock position, low, and opening. I don't think we came within 500 ft of one another. We tried to communicate with bay approach but there was so much yak yak on the frequency that communication was impossible in either direction. I talked to bay approach on the telephone after we landed and sent a TCASII report to our airline and thought that was the end of it. Evidently it isn't, so I am submitting a captain's report and a NASA report. Supplemental information from acn 309107: on aircraft Y, I was the PF on a vector to final. Center gave us a heading and told us to contact approach. The captain made several attempts to check in with approach but an obviously harried approach controller did not respond to any of our xmissions. We then received a TCASII RA with a 757 at our 12 O'clock position. Our RA was for a descent. I disconnected the autoplt and pushed the nose over. Simultaneously I observed the 757 climbing. Bay approach then told us to 'turn east immediately.' I started a turn to the right but seeing the aforementioned 757, rolled back to the left. I climbed back to 11000 ft. The PNF advised of entering the TCASII maneuver.

Original NASA ASRS Text

Title: LGT AND MLG BOTH HAVE TCASII RA'S AND RESPOND AS INDICATED.

Narrative: WE WERE LEVEL AT 11000 FT ON OUR DSCNT INTO SFO, ON A RADAR VECTOR WHEN WE GOT A TCASII RA TO CLB. WE CLBED IMMEDIATELY AND AT 11500 FT WE GOT A 'CLR OF CONFLICT.' IN THE MEANTIME WE SIGHTED THE OTHER ACFT ABOUT 1:30 O'CLOCK POS, LOW, AND OPENING. I DON'T THINK WE CAME WITHIN 500 FT OF ONE ANOTHER. WE TRIED TO COMMUNICATE WITH BAY APCH BUT THERE WAS SO MUCH YAK YAK ON THE FREQ THAT COM WAS IMPOSSIBLE IN EITHER DIRECTION. I TALKED TO BAY APCH ON THE TELEPHONE AFTER WE LANDED AND SENT A TCASII RPT TO OUR AIRLINE AND THOUGHT THAT WAS THE END OF IT. EVIDENTLY IT ISN'T, SO I AM SUBMITTING A CAPT'S RPT AND A NASA RPT. SUPPLEMENTAL INFO FROM ACN 309107: ON ACFT Y, I WAS THE PF ON A VECTOR TO FINAL. CTR GAVE US A HDG AND TOLD US TO CONTACT APCH. THE CAPT MADE SEVERAL ATTEMPTS TO CHK IN WITH APCH BUT AN OBVIOUSLY HARRIED APCH CTLR DID NOT RESPOND TO ANY OF OUR XMISSIONS. WE THEN RECEIVED A TCASII RA WITH A 757 AT OUR 12 O'CLOCK POS. OUR RA WAS FOR A DSCNT. I DISCONNECTED THE AUTOPLT AND PUSHED THE NOSE OVER. SIMULTANEOUSLY I OBSERVED THE 757 CLBING. BAY APCH THEN TOLD US TO 'TURN E IMMEDIATELY.' I STARTED A TURN TO THE R BUT SEEING THE AFOREMENTIONED 757, ROLLED BACK TO THE L. I CLBED BACK TO 11000 FT. THE PNF ADVISED OF ENTERING THE TCASII MANEUVER.

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.