ZOA controller and air carrier first officer reported the aircraft was issued a descent clearance to...

Narrative:

Aircraft X was descending via suttr into smf via the ait procedure following another aircraft into smf. Aircraft Y was descending via dyamd into sfo. I was by myself working a number of aircraft and was not paying close attention to aircraft X. I was assuming he would make the crossing restrictions on the suutr arrival. The important one is foolz at FL210 or below. One minute from losing possible separation; nct sector sunol called me and said aircraft X was going to be high for all the restrictions. She mentioned he was too high and too fast. Aircraft X was out of FL268 at this point; so I hung up and immediately stopped aircraft Y at FL270. Aircraft X crossed foolz at 24700 which is 3700 feet too high. Aircraft Y could legally be down at FL220 at that point. This is very dangerous.I have written a report on this issue before where the sfo arrival was already down at FL220 and I had to turn him hard to ensure separation. There is 5.1 miles and 1000 ft difference in the crossing restrictions on the suutr and dyamd arrivals. This is way too close. What would have happened if my sfo arrival had been down at FL220 and [the other aircraft] is in max descent rate trying to make the restriction? In the situation yesterday they easily could be at the exact same place at the same altitude and who knows if TCAS cold save it.the chief pilot for [aircraft X's airline] called and said he would have a discussion about letting ATC know earlier about missing restrictions. He also mentioned this is happening a lot and blamed it on the winglets on the B737 saying it is much more difficult to descend quickly when the airspeed is pulled back. I believe also that the previous sector may have issued the descent a little late. Again; change the crossing restrictions to at least 10 miles apart on these two arrivals. It is only a matter of time until there is an extremely dangerous confliction with these two procedures that results in loss of life.

Original NASA ASRS Text

Title: ZOA Controller and air carrier First Officer reported the aircraft was issued a descent clearance too late to comply with a crossing restriction which caused a conflict with other traffic.

Narrative: Aircraft X was descending via SUTTR into SMF via the AIT procedure following another aircraft into SMF. Aircraft Y was descending VIA DYAMD into SFO. I was by myself working a number of aircraft and was not paying close attention to Aircraft X. I was assuming he would make the crossing restrictions on the SUUTR arrival. The important one is FOOLZ at FL210 or below. One minute from losing possible separation; NCT sector SUNOL called me and said Aircraft X was going to be high for all the restrictions. She mentioned he was too high and too fast. Aircraft X was out of FL268 at this point; so I hung up and immediately stopped Aircraft Y at FL270. Aircraft X crossed FOOLZ at 24700 which is 3700 feet too high. Aircraft Y could legally be down at FL220 at that point. This is very dangerous.I have written a report on this issue before where the SFO arrival was already down at FL220 and I had to turn him hard to ensure separation. There is 5.1 miles and 1000 ft difference in the crossing restrictions on the SUUTR and DYAMD arrivals. This is way too close. What would have happened if my SFO arrival had been down at FL220 and [the other aircraft] is in max descent rate trying to make the restriction? In the situation yesterday they easily could be at the exact same place at the same altitude and who knows if TCAS cold save it.The chief pilot for [Aircraft X's airline] called and said he would have a discussion about letting ATC know earlier about missing restrictions. He also mentioned this is happening a lot and blamed it on the winglets on the B737 saying it is much more difficult to descend quickly when the airspeed is pulled back. I believe also that the previous sector may have issued the descent a little late. Again; CHANGE THE CROSSING RESTRICTIONS TO AT LEAST 10 MILES APART ON THESE TWO ARRIVALS. It is only a matter of time until there is an extremely dangerous confliction with these two procedures that results in loss of life.

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	1510022
Time
Date	201801
Local Time Of Day	1201-1800
Place
Locale Reference	ZOA.ARTCC
State Reference	CA
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR SUUTR2
Flight Plan	IFR
Aircraft 2
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR DYAMD3
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 27
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Undershoot Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Published Material / Policy

ZOA controller and air carrier first officer reported the aircraft was issued a descent clearance too late to comply with a crossing restriction which caused a conflict with other traffic.