MD80 TCASII did not show another aircraft.

Attributes
ACN	440782
Time
Date	199906
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : zfw.artcc
State Reference	TX
Altitude	msl single value : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : worth 2
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zfw.artcc
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	departure sid : worth 2
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : atp
ASRS Report	440782
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe other spatial deviation
Independent Detector	other flight crewa other flight crewb other other : 4
Resolutory Action	none taken : anomaly accepted
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Center has the mode C but TCASII does not see him. Dfw departure cleared us to 17000 ft and told us to contact ZFW on 127.0. When we checked on with ZFW they had us climb and maintain 16000 ft. Traffic was a cessna 4114 at 17000 ft. We had the TCASII in the above, 40 mi setting. Nothing was showing at the location given for the C414 and I asked the ZFW if they had a mode C readout on the C414. They said that yes they did. We were visually scanning for the traffic when the TCASII all of a sudden spotted him at the 10 mi ring. There was not a lot of other traffic on the screen that the TCASII was tracking. Maybe 5 or 6 at most. Another company flight was behind us and was held down at 16000 ft also. His flight number was Y and he also reported that he did not have him on TCASII until he broke the 10 mi ring. The cessna's tail number was aircraft Z. I have this happen several times a yr where the TCASII does not spot the traffic until under 10 mi and sometimes never even sees the traffic that the ground controllers report having a mode C readout on. Most of the time it is another airline that the TCASII does not see. Awhile ago we got a message that basically said that this cannot happen, that the TCASII sees all and knows all. The ground radar sees the traffic but the TCASII does not. Why is this so?

Original NASA ASRS Text

Title: MD80 TCASII DID NOT SHOW ANOTHER ACFT.

Narrative: CTR HAS THE MODE C BUT TCASII DOES NOT SEE HIM. DFW DEP CLRED US TO 17000 FT AND TOLD US TO CONTACT ZFW ON 127.0. WHEN WE CHKED ON WITH ZFW THEY HAD US CLB AND MAINTAIN 16000 FT. TFC WAS A CESSNA 4114 AT 17000 FT. WE HAD THE TCASII IN THE ABOVE, 40 MI SETTING. NOTHING WAS SHOWING AT THE LOCATION GIVEN FOR THE C414 AND I ASKED THE ZFW IF THEY HAD A MODE C READOUT ON THE C414. THEY SAID THAT YES THEY DID. WE WERE VISUALLY SCANNING FOR THE TFC WHEN THE TCASII ALL OF A SUDDEN SPOTTED HIM AT THE 10 MI RING. THERE WAS NOT A LOT OF OTHER TFC ON THE SCREEN THAT THE TCASII WAS TRACKING. MAYBE 5 OR 6 AT MOST. ANOTHER COMPANY FLT WAS BEHIND US AND WAS HELD DOWN AT 16000 FT ALSO. HIS FLT NUMBER WAS Y AND HE ALSO RPTED THAT HE DID NOT HAVE HIM ON TCASII UNTIL HE BROKE THE 10 MI RING. THE CESSNA'S TAIL NUMBER WAS ACFT Z. I HAVE THIS HAPPEN SEVERAL TIMES A YR WHERE THE TCASII DOES NOT SPOT THE TFC UNTIL UNDER 10 MI AND SOMETIMES NEVER EVEN SEES THE TFC THAT THE GND CTLRS RPT HAVING A MODE C READOUT ON. MOST OF THE TIME IT IS ANOTHER AIRLINE THAT THE TCASII DOES NOT SEE. AWHILE AGO WE GOT A MESSAGE THAT BASICALLY SAID THAT THIS CANNOT HAPPEN, THAT THE TCASII SEES ALL AND KNOWS ALL. THE GND RADAR SEES THE TFC BUT THE TCASII DOES NOT. WHY IS THIS SO?

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.