TCASII logic air carrier X TCASII RA with VFR aircraft got unsafe RA.

Attributes
ACN	313775
Time
Date	199508
Place
Locale Reference	atc facility : pxr
State Reference	AZ
Altitude	msl bound lower : 3400 msl bound upper : 3400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phx
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7400 flight time type : 740
ASRS Report	313775
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 10000 flight time type : 4000
ASRS Report	313777
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 500 vertical : 800
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On the eagul 3 departure from phx we experienced a traffic conflict and a TCASII resolution which I feel was unsafe. I was the PF and did not comply with the resolution. I am concerned that there may be a software problem with the TCASII in this situation. I was just completing the turn to 020 degrees at approximately 6 DME from pxr and 3400 ft (2200 ft AGL), I observed a high wing cessna slightly below at 11 O'clock maybe 4 mi ahead. At the same time we received a TCASII alert and a call from departure control for a TA. I immediately checked the vsi which showed the conflict at 12 O'clock, 2-3 mi, 400 ft below with our rate of climb at 500 FPM. (The copilot confirmed all these figures.) we were at 230 KTS accelerating (vzf 228) with quiet EPR (approximately 1.57). I was not too concerned at this time since we were above the aircraft climbing and he was 45 degrees off our heading. I did increase the back pressure slightly. About 15 seconds after the TCASII alert we received an RA commanding a 1500 FPM descent. I hesitated initially but decided to ignore the TCASII. The so, copilot and I had the traffic in sight. We were at this time at least 500 ft above and climbing in excess of 500 FPM and only 2500-2800 ft above the ground with rising terrain. We received a second more intense RA (for a descent) at which time I pulled back hard increasing the rate of climb needle to beyond vertical (greater than 1500 FPM). Within 5-10 seconds of the second RA we received monitor vertical speed followed immediately thereafter by a clear of conflict. Within 5 seconds of the clear of conflict advisory the traffic disappeared below the aircraft to the left. I discussed the situation with departure. He confirmed that the aircraft was in the phx pattern at 3000 ft under his control and that he did not receive a conflict alert. I feel if I had followed the TCASII it would have put us in imminent danger of a midair followed by a GPWS alert. I feel that the TCASII program needs work.

Original NASA ASRS Text

Title: TCASII LOGIC ACR X TCASII RA WITH VFR ACFT GOT UNSAFE RA.

Narrative: ON THE EAGUL 3 DEP FROM PHX WE EXPERIENCED A TFC CONFLICT AND A TCASII RESOLUTION WHICH I FEEL WAS UNSAFE. I WAS THE PF AND DID NOT COMPLY WITH THE RESOLUTION. I AM CONCERNED THAT THERE MAY BE A SOFTWARE PROB WITH THE TCASII IN THIS SIT. I WAS JUST COMPLETING THE TURN TO 020 DEGS AT APPROX 6 DME FROM PXR AND 3400 FT (2200 FT AGL), I OBSERVED A HIGH WING CESSNA SLIGHTLY BELOW AT 11 O'CLOCK MAYBE 4 MI AHEAD. AT THE SAME TIME WE RECEIVED A TCASII ALERT AND A CALL FROM DEP CTL FOR A TA. I IMMEDIATELY CHKED THE VSI WHICH SHOWED THE CONFLICT AT 12 O'CLOCK, 2-3 MI, 400 FT BELOW WITH OUR RATE OF CLB AT 500 FPM. (THE COPLT CONFIRMED ALL THESE FIGURES.) WE WERE AT 230 KTS ACCELERATING (VZF 228) WITH QUIET EPR (APPROX 1.57). I WAS NOT TOO CONCERNED AT THIS TIME SINCE WE WERE ABOVE THE ACFT CLBING AND HE WAS 45 DEGS OFF OUR HDG. I DID INCREASE THE BACK PRESSURE SLIGHTLY. ABOUT 15 SECONDS AFTER THE TCASII ALERT WE RECEIVED AN RA COMMANDING A 1500 FPM DSCNT. I HESITATED INITIALLY BUT DECIDED TO IGNORE THE TCASII. THE SO, COPLT AND I HAD THE TFC IN SIGHT. WE WERE AT THIS TIME AT LEAST 500 FT ABOVE AND CLBING IN EXCESS OF 500 FPM AND ONLY 2500-2800 FT ABOVE THE GND WITH RISING TERRAIN. WE RECEIVED A SECOND MORE INTENSE RA (FOR A DSCNT) AT WHICH TIME I PULLED BACK HARD INCREASING THE RATE OF CLB NEEDLE TO BEYOND VERT (GREATER THAN 1500 FPM). WITHIN 5-10 SECONDS OF THE SECOND RA WE RECEIVED MONITOR VERT SPD FOLLOWED IMMEDIATELY THEREAFTER BY A CLR OF CONFLICT. WITHIN 5 SECONDS OF THE CLR OF CONFLICT ADVISORY THE TFC DISAPPEARED BELOW THE ACFT TO THE L. I DISCUSSED THE SIT WITH DEP. HE CONFIRMED THAT THE ACFT WAS IN THE PHX PATTERN AT 3000 FT UNDER HIS CTL AND THAT HE DID NOT RECEIVE A CONFLICT ALERT. I FEEL IF I HAD FOLLOWED THE TCASII IT WOULD HAVE PUT US IN IMMINENT DANGER OF A MIDAIR FOLLOWED BY A GPWS ALERT. I FEEL THAT THE TCASII PROGRAM NEEDS WORK.

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.