A B767 CREW NOTES THE ACFT DID NOT AUTOMATICALLY DSND TO MEET AN ENTERED XING RESTR. THE PROPER VNAV MODE MAY NOT HAVE BEEN SELECTED.

Narrative

CTR GAVE US A CLRNC TO CROSS ZARDA INTXN AT FL290 APPROX 60 NM FROM ZARDA WHILE CRUISING AT FL330. AS PLT MONITORING; I SET FL290 IN THE MCP ALT WINDOW; AND HAD PREVIOUSLY PUT ZARDA AT FL290 IN THE FMC LEGS PAGES AS THIS IS A STANDARD XING CLRNC AT ZARDA. AT 9 NM FROM ZARDA; I TOLD THE FO I WAS GETTING UP TO USE THE HEAD PRIOR TO TOP OF DSCNT. UPON RETURNING TO THE SEAT; THE FO INFORMED ME WE HAD BEEN GIVEN A FREQ CHANGE AND A NEW XPONDER CODE. THIS WAS IMMEDIATELY FOLLOWED BY ATC ASKING IF WE WERE GOING TO MAKE THE XING RESTR. I LOOKED AT THE EHSI AND SAW WE WERE AT ZARDA; BUT WE HAD YET TO START DOWN. I TOLD ATC; 'SORRY; WE WILL NOT MAKE THE RESTR BUT WILL DSND AS RAPIDLY AS POSSIBLE.' ATC REPLIED; 'NO PROB; NOW DSND TO FL230.' I THEN SELECTED FLT LEVEL CHANGE AND EXTENDED THE SPD BRAKES AND ASKED THE FO WHAT HAPPENED. HE THOUGHT (AS HAD I) THAT WE WERE IN VNAV AND THE AIRPLANE SHOULD HAVE STARTED DOWN TO MAKE THE RESTR. I BELIEVE HE BECAME DISTR BY THE FREQ AND XPONDER CODE CHANGES. THE CHAIN LEADING TO THIS MAY HAVE STARTED WAY BACK ON OUR CLB TO CRUISE. OUR FLT PLAN WAS TO CRUISE AT FL350. ATC HELD US AT FL330 FOR A WHILE AND WHEN I INQUIRED AS TO WHEN WE COULD EXPECT FL350 THE CTLR INFORMED US FL350 WAS RPTING CONTINUOUS MODERATE TURB. WE ELECTED TO STAY AT FL330 WHICH WAS EXPERIENCING CONTINUOUS LIGHT AND OCCASIONAL MODERATE TURB. SHORTLY THEREAFTER; THE FO SELECTED THE CRUISE PAGE AND ENTERED FL330 AS OUR CRUISE ALT. I'M NOT SURE IF VNAV WAS THEN (OR EVER) SELECTED. I SEEM TO RECALL SEEING VNAV PATH ON MY FMA; BUT MAYBE THAT IS JUST WHAT I EXPECTED TO SEE; OR I WAS RECALLING ANOTHER FLT. EVIDENTLY; VNAV HAD NOT BEEN SELECTED. I SHOULD NOT HAVE WAITED SO LONG TO TAKE CARE OF MY PHYSIOLOGICAL NEEDS. NEXT TIME I'LL MAKE SURE I AM IN THE SEAT APCHING A TOP OF DSCNT POINT. I MAY HAVE BEEN LULLED INTO COMPLACENCY AS MY FO ON THIS LEG IS A CURRENT QUALIFIED CAPT AND SIMULATOR INSTRUCTOR. I AM AN IOE INSTRUCTOR. HE AND I HAD JUST BEEN DISCUSSING DSCNT PLANNING AND I WAS EXPLAINING MY TECHNIQUE FOR SETTING UP THE 'OFF PATH' DSCNT PAGE PRIOR TO MY GETTING UP. SO I GUESS I LET MY GUARD DOWN. ONE OTHER POINT: AFTERWARDS; WE TRIED TO TRACE THE CHAIN THAT LED UP TO THE INCIDENT. AFTER ENTERING FL330 AS THE CRUISE ALT ON THE CRUISE PAGE; WHILE WE WERE IN ALT HOLD AT FL330 IS POSSIBLE THE FMA CHANGES TO VNAV PATH? NEITHER ONE OF US COULD REMEMBER. SOMETHING I'LL CHK ON MY NEXT FLT. IF THAT'S WHAT HAPPENED; THAT MIGHT EXPLAIN WHY VNAV WAS NOT THEN SELECTED ON THE MCP. SUPPLEMENTAL INFO FROM ACN 677001: IN THE FUTURE I WILL NOT ALLOW MYSELF TO BECOME PREOCCUPIED WITH OTHER DUTIES AT SUCH A CRITICAL PHASE OF FLT. I WILL LOOK INTO THE FMC AND FIND OUT EXACTLY HOW MANY MI TO TOP OF DSCNT INSTEAD OF JUDGING DISTANCE ON A CLUTTERED HSI SCREEN. I BELIEVE THIS WAS A CLASSIC EXAMPLE OF AUTOMATION COMPLACENCY. THE CAPT AND I DISCUSSED THE ISSUE OF FMA READING ALT CAPTURE VERSUS VNAV PATH AND COULD NOT RECALL WHEN ALT CAPTURE BECAME THE ACTIVE PITCH MODE.