A B737-ng aircraft on the sjc silcn 1 RNAV profile was cleared to cross the vlley waypoint at FL200 ...

Narrative:

While approaching the troxx waypoint on the silcn 1 RNAV arrival; oakland center cleared the flight via the silcn 1 arrival; maintain FL340. The flight was not cleared to descend via. Later; oakland center cleared the flight to descend pilot discretion FL240. The arrival was properly briefed and verified per the arrival chart and FMC. Silcn 1 RNAV has the silcn waypoint at 280 knots; at or above FL200. The aircraft was engaged in VNAV/LNAV; with the autothrottle engaged and on path. Approximately 12 NM from silcn; oakland center cleared the flight to cross silcn at 280 knots; at FL200. The pilot flying entered the altitude restriction of FL200 into the FMC; verified and executed. The path was recalculated and was now showing 3800 feet high. Oakland center was informed of this; and the pilot monitoring requested relief from the crossing restriction. Oakland center stated to 'do the best you can.' the speedbrake was full deployed; at approximately 15 NM prior to the vlley waypoint; the aircraft leveled off at FL200. The flight was switched to norcal approach; and one has to communicate quickly with them to continue the descent for future crossing restrictions. We were still not cleared to descend via the arrival. Norcal issued a clearance to descend via the silcn 1; landing northwest. This clearance was issued at the top of descent for the FMC.recommend changing the STAR for the crossing restriction at the silcn waypoint to be at FL200 instead of at or above FL200. This may change the troxx waypoint altitude crossing restriction as well. Recommend oakland center does not issue an altitude crossing restriction while 12 NM from the sicln waypoint. This altitude restriction cannot be met when given an airspeed restriction for the arrival. If silcn crossing restriction is always going to be FL200; this needs to be advised to the flight crews prior to the troxx waypoint; and not while on the descent path.

Original NASA ASRS Text

Title: A B737-NG aircraft on the SJC SILCN 1 RNAV profile was cleared to cross the VLLEY waypoint at FL200 when the aircraft was 15 NM from that point. The crew told ATC unable.

Narrative: While approaching the TROXX waypoint on the SILCN 1 RNAV Arrival; Oakland Center cleared the flight via the SILCN 1 Arrival; maintain FL340. The flight was not cleared to descend via. Later; Oakland Center cleared the flight to descend Pilot Discretion FL240. The arrival was properly briefed and verified per the arrival chart and FMC. SILCN 1 RNAV has the SILCN waypoint at 280 knots; at or above FL200. The aircraft was engaged in VNAV/LNAV; with the autothrottle engaged and on path. Approximately 12 NM from SILCN; Oakland Center cleared the flight to cross SILCN at 280 knots; at FL200. The Pilot Flying entered the altitude restriction of FL200 into the FMC; verified and executed. The path was recalculated and was now showing 3800 feet high. Oakland Center was informed of this; and the Pilot Monitoring requested relief from the crossing restriction. Oakland Center stated to 'Do the best you can.' The speedbrake was full deployed; at approximately 15 NM prior to the VLLEY waypoint; the aircraft leveled off at FL200. The flight was switched to NorCal Approach; and one has to communicate quickly with them to continue the descent for future crossing restrictions. We were still not cleared to descend via the arrival. NorCal issued a clearance to descend via the SILCN 1; landing northwest. This clearance was issued at the Top of Descent for the FMC.Recommend changing the STAR for the crossing restriction at the SILCN waypoint to be at FL200 instead of at or above FL200. This may change the TROXX waypoint altitude crossing restriction as well. Recommend Oakland Center does not issue an altitude crossing restriction while 12 NM from the SICLN waypoint. This altitude restriction cannot be met when given an airspeed restriction for the arrival. If SILCN crossing restriction is always going to be FL200; this needs to be advised to the flight crews prior to the TROXX waypoint; and not while on the descent path.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1255769
Time
Date	201504
Local Time Of Day	1801-2400
Place
Locale Reference	ZOA.ARTCC
State Reference	CA
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Make Model Name	B737 Next Generation Undifferentiated
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR SILCN 1
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Flying
Events
Anomaly	ATC Issue All Types Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

A B737-ng aircraft on the sjc silcn 1 RNAV profile was cleared to cross the vlley waypoint at FL200 when the aircraft was 15 NM from that point. The crew told ATC unable.