Altitude deviation altitude excursion upon receiving TCASII RA.

Attributes
ACN	228828
Time
Date	199212
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sfo
State Reference	CA
Altitude	msl bound lower : 4000 msl bound upper : 4600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sfo
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft
Flight Phase	cruise other
Route In Use	enroute : on vectors
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 10000
ASRS Report	228828
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 1500 vertical : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Sfo bay approach advised us of traffic at 10 O'clock and cleared us for a visual approach to runway 28 at sfo. We were east of the 095 degree radial of sfo and were to turn left to intercept. Our altitude was 4000 MSL we were in level flight and our TCASII gave us an RA 'climb', I climbed to 4600 and looked at 3 O'clock to see a small aircraft at a very low altitude. The RA stopped and I began my descent after consulting with ATC. This is where it gets interesting. ATC continued to challenge our judgement and action in responding to the RA. They tried to make a point that they knew where the traffic was and there was no conflict. When in fact the female controller had erred in calling out traffic at 10 O'clock when in fact it was at 2 O'clock. One more comment. ATC must understand that it is our responsibility to follow an RA and it is irrelevant if ATC is aware of the position of the 2 aircraft. Numerous midairs have occurred when ATC knew their positions.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION UPON RECEIVING TCASII RA.

Narrative: SFO BAY APCH ADVISED US OF TFC AT 10 O'CLOCK AND CLRED US FOR A VISUAL APCH TO RWY 28 AT SFO. WE WERE E OF THE 095 DEG RADIAL OF SFO AND WERE TO TURN L TO INTERCEPT. OUR ALT WAS 4000 MSL WE WERE IN LEVEL FLT AND OUR TCASII GAVE US AN RA 'CLB', I CLBED TO 4600 AND LOOKED AT 3 O'CLOCK TO SEE A SMALL ACFT AT A VERY LOW ALT. THE RA STOPPED AND I BEGAN MY DSCNT AFTER CONSULTING WITH ATC. THIS IS WHERE IT GETS INTERESTING. ATC CONTINUED TO CHALLENGE OUR JUDGEMENT AND ACTION IN RESPONDING TO THE RA. THEY TRIED TO MAKE A POINT THAT THEY KNEW WHERE THE TFC WAS AND THERE WAS NO CONFLICT. WHEN IN FACT THE FEMALE CTLR HAD ERRED IN CALLING OUT TFC AT 10 O'CLOCK WHEN IN FACT IT WAS AT 2 O'CLOCK. ONE MORE COMMENT. ATC MUST UNDERSTAND THAT IT IS OUR RESPONSIBILITY TO FOLLOW AN RA AND IT IS IRRELEVANT IF ATC IS AWARE OF THE POS OF THE 2 ACFT. NUMEROUS MIDAIRS HAVE OCCURRED WHEN ATC KNEW THEIR POSITIONS.

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.