B757-200 flight crew has a TCAS alert while entering holding at tnca.

Attributes
ACN	722909
Time
Date	200701
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : tnca.airport
State Reference	FO
Altitude	msl single value : 5000
Environment
Flight Conditions	Marginal
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	descent : holding descent : approach
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : tnca.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 200 flight time total : 8500 flight time type : 5600
ASRS Report	722909
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 120 flight time total : 20000 flight time type : 7000
ASRS Report	722918
Events
Anomaly	conflict : airborne less severe
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb
Resolutory Action	flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

Tnca is non radar environment. Curacao control hands off to tnca tower. The tower asks for position and sequences the planes into the holding pattern at different altitudes. We were 1 hour late due to a mechanical problem (no APU). We arrived within mins of the ord-aua flight XXX. We heard them reporting their position and tower directing them to hold. There was also a YYY flight ahead of XXX and another cessna in the pattern. We were handed off to tower at 15 mi north of the field at 8000 ft. Tower directed us to proceed to the VOR and hold. We were also cleared to descend to 5000 ft. Captain was flying on 'C' autoplt; flaps 5 degrees and around 220 KTS. As we proceeded to cross the VOR at about 6600 ft; we noticed on TCAS the XXX inbound (opposite direction as we were) at 5000 ft. Tower was busy talking to other traffic. I pointed out the potential conflict to the captain and he slowed his descent. At about 5500 ft we started to get a TA and captain started to climb. At that time the tower asked XXX what their altitude was and asked them to descend to 2500 ft. He told us to descend to 5000 ft. It is our opinion that tower confused the flts and did not intend to descend us to 5000 ft initially. After exiting the hold and given clearance for a visual; tower asked numerous times for position and altitudes. It seemed like they were unaware of anyone's position. I have flown here several times before and it is challenging and always up to the pilots to ensure safe separation!

Original NASA ASRS Text

Title: B757-200 FLT CREW HAS A TCAS ALERT WHILE ENTERING HOLDING AT TNCA.

Narrative: TNCA IS NON RADAR ENVIRONMENT. CURACAO CTL HANDS OFF TO TNCA TWR. THE TWR ASKS FOR POS AND SEQUENCES THE PLANES INTO THE HOLDING PATTERN AT DIFFERENT ALTS. WE WERE 1 HR LATE DUE TO A MECHANICAL PROB (NO APU). WE ARRIVED WITHIN MINS OF THE ORD-AUA FLT XXX. WE HEARD THEM RPTING THEIR POS AND TWR DIRECTING THEM TO HOLD. THERE WAS ALSO A YYY FLT AHEAD OF XXX AND ANOTHER CESSNA IN THE PATTERN. WE WERE HANDED OFF TO TWR AT 15 MI N OF THE FIELD AT 8000 FT. TWR DIRECTED US TO PROCEED TO THE VOR AND HOLD. WE WERE ALSO CLRED TO DSND TO 5000 FT. CAPT WAS FLYING ON 'C' AUTOPLT; FLAPS 5 DEGS AND AROUND 220 KTS. AS WE PROCEEDED TO CROSS THE VOR AT ABOUT 6600 FT; WE NOTICED ON TCAS THE XXX INBOUND (OPPOSITE DIRECTION AS WE WERE) AT 5000 FT. TWR WAS BUSY TALKING TO OTHER TFC. I POINTED OUT THE POTENTIAL CONFLICT TO THE CAPT AND HE SLOWED HIS DSCNT. AT ABOUT 5500 FT WE STARTED TO GET A TA AND CAPT STARTED TO CLB. AT THAT TIME THE TWR ASKED XXX WHAT THEIR ALT WAS AND ASKED THEM TO DSND TO 2500 FT. HE TOLD US TO DSND TO 5000 FT. IT IS OUR OPINION THAT TWR CONFUSED THE FLTS AND DID NOT INTEND TO DSND US TO 5000 FT INITIALLY. AFTER EXITING THE HOLD AND GIVEN CLRNC FOR A VISUAL; TWR ASKED NUMEROUS TIMES FOR POS AND ALTS. IT SEEMED LIKE THEY WERE UNAWARE OF ANYONE'S POS. I HAVE FLOWN HERE SEVERAL TIMES BEFORE AND IT IS CHALLENGING AND ALWAYS UP TO THE PLTS TO ENSURE SAFE SEPARATION!

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.