Commercial Fixed Wing
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9
Situational Awareness; Time Pressure
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
General None Reported / Taken
Human Factors; Procedure
I cleared Aircraft X to 110 but meant to say 130. I questioned the clearance in my head as I heard him read it back but couldn't really remember if I had said 110 or 130... but he was going to be clear of the terrain in just over one minute anyway; so I thought I could just watch the descent rate instead of clarifying the clearance. I was wrong. He descended very quickly and by the time I tried to stop him; it was too late. I should have clarified immediately instead of watching to see the descent rate.
ZOA ARTCC Controller reported questioning whether a readback was read back correctly and did not clarify the altitude with the aircraft in time; resulting in a MVA violation.