Md-80 continues climb while TCASII indicates descend. Near midair collision.

Attributes
ACN	289937
Time
Date	199411
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : fat
State Reference	CA
Altitude	msl bound lower : 8500 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sdf
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors enroute airway : fat
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12000 flight time type : 3500
ASRS Report	289937
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	other
Consequence	other
Miss Distance	horizontal : 500 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

On a vector heading 040 degrees climbing out of fresno, departure advised VFR traffic at about 1:30 or 2 O'clock position at 8500 ft. We were told to level off at 8000 ft. Climbing through about 6500 ft we made visual contact with traffic and advised departure control, at which time they told us to continue to 10000 ft and maintain visual separation. TCASII had by then given us a TA. I judged by our relative motion that the traffic would pass behind us by a safe margin and continued the climb. As we got closer it appeared we were on converging courses. Judging our rate of climb and the distance between us I elected to continue the climb even though the TCASII was now telling us to descend. I figured our rate of climb made it unwise to descend. We had enough energy to make an evasive maneuver but I didn't feel it was necessary. As we passed the traffic we realized it was a much closer encounter than we had planned on. On receiving departure controls initial advisory on the traffic, I commented that it made good sense to level off at 8000 ft. Why I continued to climb after they told us to maintain our own separation, I don't know. At the time it didn't look close. In retrospect, it was very close. This whole episode was stupidity personified on my part. I was glad none of the passenger asked us if we had seen the light airplane we passed, because I couldn't think of any honest and sane answers.

Original NASA ASRS Text

Title: MD-80 CONTINUES CLB WHILE TCASII INDICATES DSND. NMAC.

Narrative: ON A VECTOR HDG 040 DEGS CLBING OUT OF FRESNO, DEP ADVISED VFR TFC AT ABOUT 1:30 OR 2 O'CLOCK POS AT 8500 FT. WE WERE TOLD TO LEVEL OFF AT 8000 FT. CLBING THROUGH ABOUT 6500 FT WE MADE VISUAL CONTACT WITH TFC AND ADVISED DEP CTL, AT WHICH TIME THEY TOLD US TO CONTINUE TO 10000 FT AND MAINTAIN VISUAL SEPARATION. TCASII HAD BY THEN GIVEN US A TA. I JUDGED BY OUR RELATIVE MOTION THAT THE TFC WOULD PASS BEHIND US BY A SAFE MARGIN AND CONTINUED THE CLB. AS WE GOT CLOSER IT APPEARED WE WERE ON CONVERGING COURSES. JUDGING OUR RATE OF CLB AND THE DISTANCE BTWN US I ELECTED TO CONTINUE THE CLB EVEN THOUGH THE TCASII WAS NOW TELLING US TO DSND. I FIGURED OUR RATE OF CLB MADE IT UNWISE TO DSND. WE HAD ENOUGH ENERGY TO MAKE AN EVASIVE MANEUVER BUT I DIDN'T FEEL IT WAS NECESSARY. AS WE PASSED THE TFC WE REALIZED IT WAS A MUCH CLOSER ENCOUNTER THAN WE HAD PLANNED ON. ON RECEIVING DEP CTLS INITIAL ADVISORY ON THE TFC, I COMMENTED THAT IT MADE GOOD SENSE TO LEVEL OFF AT 8000 FT. WHY I CONTINUED TO CLB AFTER THEY TOLD US TO MAINTAIN OUR OWN SEPARATION, I DON'T KNOW. AT THE TIME IT DIDN'T LOOK CLOSE. IN RETROSPECT, IT WAS VERY CLOSE. THIS WHOLE EPISODE WAS STUPIDITY PERSONIFIED ON MY PART. I WAS GLAD NONE OF THE PAX ASKED US IF WE HAD SEEN THE LIGHT AIRPLANE WE PASSED, BECAUSE I COULDN'T THINK OF ANY HONEST AND SANE ANSWERS.

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.