B757 TCASII RA on approach ewr.

Attributes
ACN	431723
Time
Date	199903
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ewr.airport
State Reference	NJ
Altitude	msl bound lower : 4000 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Night
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : multi engine pilot : atp
Experience	flight time last 90 days : 200 flight time total : 14000 flight time type : 1600
ASRS Report	431723
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne critical other anomaly other
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took precautionary avoidance action
Miss Distance	horizontal : 400 vertical : 3000
Supplementary
Problem Areas	Airport ATC Human Performance
Primary Problem	Airport
Air Traffic Incident	other

Narrative:

We were on approach control, assigned 160 KTS and descending to 4000 ft. I noticed traffic on TCASII (amber) at 4000 ft level 11 O'clock position. I thought he was going to go behind us by initially looking at display. I told first officer I was going to keep descent rate slow so we did not get an TA alert and to try and ask approach about traffic. He could not get a word in to approach. At approximately 4400 ft it became obvious to me that we were on a potential collision course and I started to climb telling first officer to tell approach, at the same time we started getting a climb command from TCASII. We climbed to 4500-4600 ft, traffic went under us. We then continued to 4000 ft and completed the rest of the approach uneventfully. To be honest I have not been a big TCASII fan having seen at least 6 instances where the warnings were not valid. However, in this case the display allowed us to find the target (night, lots of city lights) visually and confirmed what we were seeing to allow us to avoid the traffic.

Original NASA ASRS Text

Title: B757 TCASII RA ON APCH EWR.

Narrative: WE WERE ON APCH CTL, ASSIGNED 160 KTS AND DSNDING TO 4000 FT. I NOTICED TFC ON TCASII (AMBER) AT 4000 FT LEVEL 11 O'CLOCK POS. I THOUGHT HE WAS GOING TO GO BEHIND US BY INITIALLY LOOKING AT DISPLAY. I TOLD FO I WAS GOING TO KEEP DSCNT RATE SLOW SO WE DID NOT GET AN TA ALERT AND TO TRY AND ASK APCH ABOUT TFC. HE COULD NOT GET A WORD IN TO APCH. AT APPROX 4400 FT IT BECAME OBVIOUS TO ME THAT WE WERE ON A POTENTIAL COLLISION COURSE AND I STARTED TO CLB TELLING FO TO TELL APCH, AT THE SAME TIME WE STARTED GETTING A CLB COMMAND FROM TCASII. WE CLBED TO 4500-4600 FT, TFC WENT UNDER US. WE THEN CONTINUED TO 4000 FT AND COMPLETED THE REST OF THE APCH UNEVENTFULLY. TO BE HONEST I HAVE NOT BEEN A BIG TCASII FAN HAVING SEEN AT LEAST 6 INSTANCES WHERE THE WARNINGS WERE NOT VALID. HOWEVER, IN THIS CASE THE DISPLAY ALLOWED US TO FIND THE TARGET (NIGHT, LOTS OF CITY LIGHTS) VISUALLY AND CONFIRMED WHAT WE WERE SEEING TO ALLOW US TO AVOID THE TFC.

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.