Narrative:

The new DYAMD4 arrival at sfo is not flyable as published. The last point (archi) has a mandatory 7000 ft. Altitude restriction. The point just prior to that is at or above 8600 ft. Those points are only 4 miles apart. Descending 1600 ft. In 4 miles doesn't work (how did that even make it past the design phase?). Consequently; ATC is assigning everyone 8000 ft. At archi (like it used to be prior to this revision).this is problematic because it almost always results in non-standard phraseology being used by the controller. It also results in last-minute reprogramming of the FMC; which causes a loss of VNAV path information while it recomputes. As an example; yesterday the phraseology was something like this: descend and maintain 8000 at archi and after archi join the lateral course only for the FMS bridge visual 28R. There are obviously multiple things wrong with that.why is it every time the stars change at sfo the altitudes get messed up; resulting in multiple months of altitude exceptions and messed-up phraseology? This increases the workload for both pilots and controllers. It wasn't even a year ago when we went through this exact same problem at sfo. Do the people who design these procedures actually talk to controllers or pilots?let's try to get this fixed sooner rather than later this time.

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Original NASA ASRS Text

Title: 757 Captain reported the crossing restriction at ARCHI on the SFO DYAMD4 STAR; as published; is incorrect and requires ATC to amend the altitude.

Narrative: The new DYAMD4 arrival at SFO is not flyable as published. The last point (ARCHI) has a mandatory 7000 ft. altitude restriction. The point just prior to that is at or above 8600 ft. Those points are only 4 miles apart. Descending 1600 ft. in 4 miles doesn't work (how did that even make it past the design phase?). Consequently; ATC is assigning everyone 8000 ft. at ARCHI (like it used to be prior to this revision).This is problematic because it almost always results in non-standard phraseology being used by the controller. It also results in last-minute reprogramming of the FMC; which causes a loss of VNAV PATH information while it recomputes. As an example; yesterday the phraseology was something like this: Descend and maintain 8000 at ARCHI and after ARCHI join the lateral course only for the FMS Bridge Visual 28R. There are obviously multiple things wrong with that.Why is it every time the STARs change at SFO the altitudes get messed up; resulting in multiple months of altitude exceptions and messed-up phraseology? This increases the workload for both pilots and controllers. It wasn't even a year ago when we went through this exact same problem at SFO. Do the people who design these procedures actually talk to controllers or pilots?Let's try to get this fixed sooner rather than later this time.

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.