Less than standard separation causes TCASII TA at FL330.

Attributes
ACN	274168
Time
Date	199406
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mmid
State Reference	FO
Altitude	msl bound lower : 33000 msl bound upper : 34000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : direct enroute airway : mmid
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 60 flight time total : 16400 flight time type : 5000
ASRS Report	274168
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : atp pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Miss Distance	horizontal : 1000 vertical : 1100
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error
Situations
ATC Facility	other physical facility procedure or policy : unspecified

Narrative:

At cruise FL330 on R876 (nebound) in merida mmid fir/uta just about to cross desco intersection, when the TCASII gave us 'traffic traffic.' we looked and traffic was at 34000 ft sebound on ats. Aircraft was a B727 after passing us the aircraft started a descent to 33000 ft. (When the TCASII first said traffic, the traffic was 10 O'clock and 5 mi.) we were on the radio frequency of 125.8 (merida center). We could not receive merida center until marte. We did give position reports in the blind at lidam, matol, at desco. We relayed our position report to merida. We also gave a position report to merida radio on high frequency 6577 over matol at 1-10 am we were told to try him on 126.9 which we were unable to establish communication. Merida needs better communication equipment in the northwest part of their airspace.

Original NASA ASRS Text

Title: LTSS CAUSES TCASII TA AT FL330.

Narrative: AT CRUISE FL330 ON R876 (NEBOUND) IN MERIDA MMID FIR/UTA JUST ABOUT TO CROSS DESCO INTXN, WHEN THE TCASII GAVE US 'TFC TFC.' WE LOOKED AND TFC WAS AT 34000 FT SEBOUND ON ATS. ACFT WAS A B727 AFTER PASSING US THE ACFT STARTED A DSCNT TO 33000 FT. (WHEN THE TCASII FIRST SAID TFC, THE TFC WAS 10 O'CLOCK AND 5 MI.) WE WERE ON THE RADIO FREQ OF 125.8 (MERIDA CTR). WE COULD NOT RECEIVE MERIDA CTR UNTIL MARTE. WE DID GIVE POS RPTS IN THE BLIND AT LIDAM, MATOL, AT DESCO. WE RELAYED OUR POS RPT TO MERIDA. WE ALSO GAVE A POS RPT TO MERIDA RADIO ON HIGH FREQ 6577 OVER MATOL AT 1-10 AM WE WERE TOLD TO TRY HIM ON 126.9 WHICH WE WERE UNABLE TO ESTABLISH COM. MERIDA NEEDS BETTER COM EQUIP IN THE NW PART OF THEIR AIRSPACE.

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.