Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	171782
Time
Date	199103
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cun
State Reference	FO
Altitude	msl bound lower : 1000 msl bound upper : 1500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cun
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach landing : missed approach
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7000 flight time type : 3500
ASRS Report	171782
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 550
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

On VOR DME-1 runway 12 approach to cancun, air carrier X descended to MDA. At missed approach point we were unable to land due to rain shower and executed missed approach. On climb out (straight out), just short of 1000' MSL, we saw air carrier Y opp direction just above us (inbound to VOR in holding pattern). We leveled off and asked tower what the altitude of the other aircraft was. We believe he said 1500' MSL.. We remained just under 1000' until well clear and on another approach. It seems like the control of aircraft is fairly sloppy. It pays to listen up for other traffic in the area when flying or out of cancun.

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: ON VOR DME-1 RWY 12 APCH TO CANCUN, ACR X DSNDED TO MDA. AT MISSED APCH POINT WE WERE UNABLE TO LAND DUE TO RAIN SHOWER AND EXECUTED MISSED APCH. ON CLBOUT (STRAIGHT OUT), JUST SHORT OF 1000' MSL, WE SAW ACR Y OPP DIRECTION JUST ABOVE US (INBND TO VOR IN HOLDING PATTERN). WE LEVELED OFF AND ASKED TWR WHAT THE ALT OF THE OTHER ACFT WAS. WE BELIEVE HE SAID 1500' MSL.. WE REMAINED JUST UNDER 1000' UNTIL WELL CLR AND ON ANOTHER APCH. IT SEEMS LIKE THE CTL OF ACFT IS FAIRLY SLOPPY. IT PAYS TO LISTEN UP FOR OTHER TFC IN THE AREA WHEN FLYING OR OUT OF CANCUN.

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.