B737-700
Flight Crew Last 90 Days 183
Workload; Situational Awareness; Confusion
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance; Flight Crew Requested ATC Assistance / Clarification
Chart Or Publication; Procedure; Airport
Approaching waypoint SSEBB on the SJC SILCN 1 Arrival Runway 30L transition at 280 knots on path; a quick check of the Fix page showed us approximately 3000' high on the glidepath to runway and increasing as the aircraft slowed to 240 knots for the SSEBB speed restriction.  Just inside SSEBB; at about 27 miles; I was about to call for the landing gear to help with the descent and was given a vector east by ATC to help with the descent.  I asked Approach if they had seen the same results with other aircraft on the SILCN 1 and they replied yes. The obvious reason is that there are no hard altitudes to hit on the arrival to at least get the aircraft in the ballpark of a normal descent into SJC.  At SSEBB you are approximately 29 miles from the field having slowed to 240 knots and driving even higher.  We submitted a report to reasses/fix the arrival and what the result is (potentially high on glide path).  An obvious answer is to put a hard altitude in at KLIDE for a more accurate path.  We saw it coming and were ready to adjust before the vector from ATC. There were no deviations noted and we continued to land without incident.  I have noticed other new arrivals with issues; such as the OAK EMZOH that if flown as written will have you faster than 200 knots for the SFO Class B airspace. I input 210/ knots into waypoint MYSHN to comply.  Seems like we need to take a harder look at some of the new arrivals and do some 'fine tuning'.Change the altitude at KLIDE to a hard 4000' versus at or above. I will input a hard altitude; in this case; at KLIDE for a more accurate flight path. It just seems that these details need to be worked out before an arrival is published so that Crews and ATC are not taken by surprise. SILCN Arrival on path will drive you high for Runways 30L/R.
[Report narrative contained no additional information].
A B737-700 crew on the SILCN 1 arrival was high approaching KLIDE event though the FMC indicated the aircraft was on the VNAV path. NCT stated they have seen the same result with other aircraft.