Narrative:

We're established on the wraps five arrival to smf and ZOA tells us to 'cross turlo at or below FL280, then pilot's discretion to FL240.' after starting our descent, we are switched to a new ZOA controller. As we cross turlo at FL280, the new controller tells us to 'continue our descent to cross twane at 11000 ft.' the first officer, not fully understanding the need to keep the descent going, lets the plane leveloff at FL280 and waits for the VNAV path to start the descent. After about 30 seconds, I noticed that VNAV path was not going to initiate the descent anytime soon and told him so. About the same time, the controller restated the need to start the descent to stay clear of crossing traffic. The first officer starts his descent and stays clear of the crossing traffic and crosses twane at 11000 ft. The first officer didn't fully understand the controller's clearance to 'keep the descent going.' I didn't intervene in a more timely fashion when it was clear to me the first officer was going to wait for the VNAV path to start the descent. We should have both verbally confirmed what the clearance was. The PF should confirm and tell the other crew member what mode of descent he will use to satisfy the clearance. Better terminology from the controller, such as, 'I need you to start your descent now for crossing traffic, would have been helpful.

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Original NASA ASRS Text

Title: A B737-300 CAPT, PNF, ON APCH TO SMF, DID NOT PROMPT HIS FO TO CONTINUE THE DSCNT AS ADVISED BY ATC.

Narrative: WE'RE ESTABLISHED ON THE WRAPS FIVE ARR TO SMF AND ZOA TELLS US TO 'CROSS TURLO AT OR BELOW FL280, THEN PLT'S DISCRETION TO FL240.' AFTER STARTING OUR DSCNT, WE ARE SWITCHED TO A NEW ZOA CTLR. AS WE CROSS TURLO AT FL280, THE NEW CTLR TELLS US TO 'CONTINUE OUR DSCNT TO CROSS TWANE AT 11000 FT.' THE FO, NOT FULLY UNDERSTANDING THE NEED TO KEEP THE DSCNT GOING, LETS THE PLANE LEVELOFF AT FL280 AND WAITS FOR THE VNAV PATH TO START THE DSCNT. AFTER ABOUT 30 SECONDS, I NOTICED THAT VNAV PATH WAS NOT GOING TO INITIATE THE DSCNT ANYTIME SOON AND TOLD HIM SO. ABOUT THE SAME TIME, THE CTLR RESTATED THE NEED TO START THE DSCNT TO STAY CLR OF XING TFC. THE FO STARTS HIS DSCNT AND STAYS CLR OF THE XING TFC AND CROSSES TWANE AT 11000 FT. THE FO DIDN'T FULLY UNDERSTAND THE CTLR'S CLRNC TO 'KEEP THE DSCNT GOING.' I DIDN'T INTERVENE IN A MORE TIMELY FASHION WHEN IT WAS CLR TO ME THE FO WAS GOING TO WAIT FOR THE VNAV PATH TO START THE DSCNT. WE SHOULD HAVE BOTH VERBALLY CONFIRMED WHAT THE CLRNC WAS. THE PF SHOULD CONFIRM AND TELL THE OTHER CREW MEMBER WHAT MODE OF DSCNT HE WILL USE TO SATISFY THE CLRNC. BETTER TERMINOLOGY FROM THE CTLR, SUCH AS, 'I NEED YOU TO START YOUR DSCNT NOW FOR XING TFC, WOULD HAVE BEEN HELPFUL.

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.