B767 CREW HAD ALTDEV ON THE CIVET 4 INTO LAX.

Narrative

FLT FEB/XA/00; (JFK-LAX) IN APCH PHASE OF FLT FROM JFK TO LAX HAD EXPERIENCED AN ALTDEV. THE ACFT WAS DSNDING TO FL180 FROM FL220. APCH CTL THEN CHANGED OUR CLRNC TO FIRST SLOW TO 250 KTS THEN CLRED THE CIVET PROFILE. I FIRST SLOWED TO 250 KTS. THEN TO MAKE THE RESTR TO CROSS CIVET ABOVE 14000 FT AND AT OR BELOW 17000 FT; I HAD TO CHANGE THE FMS MODE FROM VNAV TO FLT LEVEL CHANGE; TO INCREASE RATE OF DSCNT AT A SLOWER AIRSPD IN A SHORT DISTANCE TO CIVET. WE MADE THE ALT FOR CIVET. THE NEXT RESTR WAS CROSS BREMR AT OR ABOVE 12000 FT. I WAS CHKING FOR OUTSIDE ACFT WHEN I NOTICED THAT WE WERE AT 11500 FT ABOUT 1 MI PRIOR TO BREMR. I STOPPED THE DSCNT AND CROSSED BREMR AT 11000 FT. THEN RESUMED THE CIVET PROFILE FOR AN UNEVENTFUL LNDG AT LAX. MY MISTAKE WAS TO NOT RETURN THE FMS MODE TO VNAV AFTER MAKING THE ALT RESTR AT CIVET AND THEN THE FMS WOULD CTL THE REMAINING ALT CONSTRAINTS ON THE PROFILE. THE SOCAL APCH CTL NEVER QUESTIONED MY ALT DURING THE APCH. WHEN GIVEN THE AIRSPD RESTR; I CANNOT REMEMBER IF THE WORDING FROM APCH CTL WAS; 'VIA THE CIVET PROFILE' OR 'DSND AT 200 KTS ON THE CIVET PROFILE.'