Narrative:

A C414 departed mfe direct mam into mexican airspace. I was working valley approach and did not talk to the C414. Mfe tower switched the C414 to monterrey center. Mfe tower next cleared air carrier DC9 for takeoff and assigned the DC9 runway heading. When I first talked to the air carrier I asked if he still had the twin cessna in sight at 11 O'clock and 1 mi. He said negative, he was not instructed to maintain visual. I issued an immediate climb through 3000 ft, maintain 10000 ft. As the DC9's altitude encoder indicated that the air carrier was above the C414 and increasing I issued a turn to the left to a heading of 350 degrees. The twin cessna was tracking between 120- 130 degrees. The turn to the left above and behind the C414 was necessary to keep the DC9 in united states airspace. A turn to the right would have crossed the rio grande into mexican airspace. The closest proximity of the 2 aircraft I would estimate to be 1/4 mi lateral and 200 ft vertical. The air carrier did advise after being cleared on course that they had a TCASII RA.

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Original NASA ASRS Text

Title: RPTED LTSS WHEN LCL CTLR RELEASES AN ACR DC9 BEHIND A C414 WITHOUT APPROPRIATE IFR SPACING.

Narrative: A C414 DEPARTED MFE DIRECT MAM INTO MEXICAN AIRSPACE. I WAS WORKING VALLEY APCH AND DID NOT TALK TO THE C414. MFE TWR SWITCHED THE C414 TO MONTERREY CTR. MFE TWR NEXT CLRED ACR DC9 FOR TKOF AND ASSIGNED THE DC9 RWY HDG. WHEN I FIRST TALKED TO THE ACR I ASKED IF HE STILL HAD THE TWIN CESSNA IN SIGHT AT 11 O'CLOCK AND 1 MI. HE SAID NEGATIVE, HE WAS NOT INSTRUCTED TO MAINTAIN VISUAL. I ISSUED AN IMMEDIATE CLB THROUGH 3000 FT, MAINTAIN 10000 FT. AS THE DC9'S ALT ENCODER INDICATED THAT THE ACR WAS ABOVE THE C414 AND INCREASING I ISSUED A TURN TO THE L TO A HDG OF 350 DEGS. THE TWIN CESSNA WAS TRACKING BTWN 120- 130 DEGS. THE TURN TO THE L ABOVE AND BEHIND THE C414 WAS NECESSARY TO KEEP THE DC9 IN UNITED STATES AIRSPACE. A TURN TO THE R WOULD HAVE CROSSED THE RIO GRANDE INTO MEXICAN AIRSPACE. THE CLOSEST PROX OF THE 2 ACFT I WOULD ESTIMATE TO BE 1/4 MI LATERAL AND 200 FT VERT. THE ACR DID ADVISE AFTER BEING CLRED ON COURSE THAT THEY HAD A TCASII RA.

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.