S56 TRACON controller and flight crew reported the pilots descended below the MVA on a crossing rest...

Attributes
ACN	1620029
Time
Date	201902
Local Time Of Day	1801-2400
Place
Locale Reference	SLC.Airport
State Reference	UT
Aircraft 1
Make Model Name	Light Transport
Operating Under FAR Part	Part 135
Flight Phase	Descent
Route In Use	STAR Delta5
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 0.5
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 61 Flight Crew Total 18515 Flight Crew Type 4000
Events
Anomaly	ATC Issue All Types Deviation - Altitude Overshoot Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT

Narrative:

Aircraft X was inbound on the delta-5 arrival. When the pilot checked in I gave him a descend via clearance. The pilot proceeded to cross drapr at 14;000 feet as published. The next waypoint is spiek at 13;000 feet. After drapr the pilot descended to 11;000 feet. I caught it just as he was leaving the 12;700 foot minimum vectoring altitude (MVA). I confirmed with the pilot that I gave him the descend via clearance and he said yes. I told him the restriction at spiek is 13;000 feet. He said something messed up with the FMS. My scan should have been better to catch that he started to descend before he was supposed to. I caught it after it was already too late. I am not sure if there is a good recommendation. Just need to be scanning to make sure that the pilot is following the instruction that was given.

Original NASA ASRS Text

Title: S56 TRACON Controller and flight crew reported the pilots descended below the MVA on a crossing restriction on the RNAV arrival.

Narrative: Aircraft X was inbound on the Delta-5 arrival. When the pilot checked in I gave him a descend via clearance. The pilot proceeded to cross DRAPR at 14;000 feet as published. The next waypoint is SPIEK at 13;000 feet. After DRAPR the pilot descended to 11;000 feet. I caught it just as he was leaving the 12;700 foot Minimum Vectoring Altitude (MVA). I confirmed with the pilot that I gave him the descend via clearance and he said yes. I told him the restriction at SPIEK is 13;000 feet. He said something messed up with the FMS. My scan should have been better to catch that he started to descend before he was supposed to. I caught it after it was already too late. I am not sure if there is a good recommendation. Just need to be scanning to make sure that the pilot is following the instruction that was given.

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.

S56 TRACON controller and flight crew reported the pilots descended below the MVA on a crossing restriction on the RNAV arrival.