Air carrier X had near midair collision evasive action taken from mlt. See and avoid concept.

Attributes
ACN	258620
Time
Date	199311
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sju
State Reference	PR
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ewr
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : mjzs
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Military Transport
Flight Phase	descent other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 15380
ASRS Report	258620
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 499 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Air carrier X established on route 6 in a flight from beef island to sju at an altitude of 8000 ft MSL. Approaching chaka intersection on a wbound heading we saw a traffic at about 2 to 3 O'clock position, same altitude as per the TCASII. We were never told about this traffic from sju approach control. I radioed approach control and told the guy that we had this traffic. He gave us instructions to descend at pilot discretion to 3000 ft and we started our descent. At this point, we found out that the traffic was an mlt. This traffic started his descent and we were converging very fast. Our TCASII advised us of the traffic, to descend, to monitor vertical speed, then to climb. We were too close at this time so we decided to turn 90 degrees to the left at about 50 degree bank angle. We lost visual contact with the mlt for about 5 seconds. When we saw the mlt again, he was below our altitude at about 3 O'clock position. After this, we turned back to our original heading and advised ATC of the near miss. These pilots on the mlt were supposed to be talking to roosevelt roads approach control while we were talking to sju ATC. Maybe there was a missing link between roosevelt roads and sju communication system.

Original NASA ASRS Text

Title: ACR X HAD NMAC EVASIVE ACTION TAKEN FROM MLT. SEE AND AVOID CONCEPT.

Narrative: ACR X ESTABLISHED ON RTE 6 IN A FLT FROM BEEF ISLAND TO SJU AT AN ALT OF 8000 FT MSL. APCHING CHAKA INTXN ON A WBOUND HDG WE SAW A TFC AT ABOUT 2 TO 3 O'CLOCK POS, SAME ALT AS PER THE TCASII. WE WERE NEVER TOLD ABOUT THIS TFC FROM SJU APCH CTL. I RADIOED APCH CTL AND TOLD THE GUY THAT WE HAD THIS TFC. HE GAVE US INSTRUCTIONS TO DSND AT PLT DISCRETION TO 3000 FT AND WE STARTED OUR DSCNT. AT THIS POINT, WE FOUND OUT THAT THE TFC WAS AN MLT. THIS TFC STARTED HIS DSCNT AND WE WERE CONVERGING VERY FAST. OUR TCASII ADVISED US OF THE TFC, TO DSND, TO MONITOR VERT SPD, THEN TO CLB. WE WERE TOO CLOSE AT THIS TIME SO WE DECIDED TO TURN 90 DEGS TO THE L AT ABOUT 50 DEG BANK ANGLE. WE LOST VISUAL CONTACT WITH THE MLT FOR ABOUT 5 SECONDS. WHEN WE SAW THE MLT AGAIN, HE WAS BELOW OUR ALT AT ABOUT 3 O'CLOCK POS. AFTER THIS, WE TURNED BACK TO OUR ORIGINAL HDG AND ADVISED ATC OF THE NEAR MISS. THESE PLTS ON THE MLT WERE SUPPOSED TO BE TALKING TO ROOSEVELT ROADS APCH CTL WHILE WE WERE TALKING TO SJU ATC. MAYBE THERE WAS A MISSING LINK BTWN ROOSEVELT ROADS AND SJU COM SYS.

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.