ACR X HAD POSSIBLE LTSS FROM COMPANY ACR. POSSIBLE SYS ERROR.

Narrative

FLT FROM SAN JOSE DEL CABO; MEXICO; TO LOS ANGELES; CA; (SJD-LAX) ON NOV/FRI/95. CLRNC FROM SJD TOWER INDICATED A RTE FROM THE SJD VOR TO LA PAZ VOR; CLB TO FL220 AND RPT LEAVING FL180. WE WERE ESTABLISHED INBOUND TO LA PAZ VOR WHEN WE RPTED LEAVING FL180. SJD TWR DIRECTED US TO SWITCH TO LA PAZ APCH CTL. WHEN WE RPTED TO LA PAZ APCH CTL THAT WE WERE LEAVING FL185 FOR FL220; APCH DIRECTED US TO MAINTAIN FL180 FOR TFC. WE CONFIRMED THE NEW ASSIGNED ALT WITH THE CTLR WHILE ARRESTING OUR 2000 PLUS FPM CLB AND RETURNING TO FL180. OUR MAXIMUM ALT WAS APPROX FL187; AND WE QUICKLY LEVELED OFF AT FL180. OPPOSING TFC INBOUND TO SJD FROM LA PAZ VOR WAS OUR OWN COMPANY ACFT. HE RPTED NO CONFLICT WITH US ON OUR 2ND (COMPANY) RADIO. THE SIT OR POTENTIAL PROB SEEMS TO STEM FROM TOO MANY HIGH PERFORMANCE ACFT BEING CTLED BY A VERY ANTIQUATED AND LOW PERFORMING AIR TFC CTL SYS. APPARENTLY THERE WAS LITTLE OR NO COORD BTWN LA PAZ APCH CTL AND SJD TWR AND 2 HIGH PERFORMANCE CIVILIAN AIRLINERS WERE TOO MUCH TO PROPERLY CTL AT THE SAME TIME.