TCAS climb RA averts near midair collision near tjsj.

Attributes
ACN	723798
Time
Date	200612
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sju.airport
State Reference	PR
Altitude	msl single value : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sju.tracon
Operator	common carrier : air carrier
Make Model Name	ATR 72
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 8
Flight Phase	descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sju.tracon
Operator	common carrier : air carrier
Make Model Name	BN-2A Mk. III/Trislander
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
ASRS Report	723798
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne critical
Independent Detector	aircraft equipment : tcas
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	Airport Environmental Factor ATC Human Performance
Primary Problem	Ambiguous

Narrative:

During the approach to tjsj we were cleared for the ILS runway 8; maintain 4400 ft till established contact tjsj tower. About 10 NM final established on the ILS localizer and GS; we had a TCAS RA commanding us to climb. My captain was flying at the time and initiated an immediate climb for about 300 ft. We visually saw a tri-islander to our 1 O'clock position going in the opposite direction wbound in level flight. The traffic was very close to us and without TCAS warning we could have had a conflict. This traffic was never pointed to us by approach nor the tower. It was a very busy day in tjsj with aircraft holding; the airspace was more saturated than usual.

Original NASA ASRS Text

Title: TCAS CLB RA AVERTS NMAC NEAR TJSJ.

Narrative: DURING THE APCH TO TJSJ WE WERE CLRED FOR THE ILS RWY 8; MAINTAIN 4400 FT TILL ESTABLISHED CONTACT TJSJ TWR. ABOUT 10 NM FINAL ESTABLISHED ON THE ILS LOC AND GS; WE HAD A TCAS RA COMMANDING US TO CLB. MY CAPT WAS FLYING AT THE TIME AND INITIATED AN IMMEDIATE CLB FOR ABOUT 300 FT. WE VISUALLY SAW A TRI-ISLANDER TO OUR 1 O'CLOCK POS GOING IN THE OPPOSITE DIRECTION WBOUND IN LEVEL FLT. THE TFC WAS VERY CLOSE TO US AND WITHOUT TCAS WARNING WE COULD HAVE HAD A CONFLICT. THIS TFC WAS NEVER POINTED TO US BY APCH NOR THE TWR. IT WAS A VERY BUSY DAY IN TJSJ WITH ACFT HOLDING; THE AIRSPACE WAS MORE SATURATED THAN USUAL.

Data retrieved from NASA's ASRS site as of January 2009 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.