Cessna 340/340A
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 8
Training / Qualification; Distraction
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Procedure; Human Factors; Airspace Structure
Aircraft X departed SNA with a filed route of V64 eastbound. We have two handoff options for this flow. One is southeast of Santiago Peak at 070 and one is joining the airway west of the peak climbing to 110. My trainee chose to use the latter handoff and climbed the aircraft to 110; thinking that it would certainly be above the 079 MVA (Minimum Vectoring Altitude) around the peak. The aircraft was climbing slowly and I prepared to turn the plane once I was sure the trainee had missed it. When it came time to take action she keyed up; but responded to another conflict that was happening in the sector. I immediately called her attention to the MVA issue and she followed with a hurried transmission to turn the aircraft. The aircraft violated the 079 MVA climbing out of 063 by about 1/2 mile. Neither of us issues a low altitude alert to the aircraft due to other issues needing action within the sector. The aircraft proceeded out of the MVA and continued to climb before being re-vectored to V64 and handed off normally. This was my fault as an instructor. I thought I had the time to save it when the trainee made the wrong transmission. I should never let an aircraft get 'one transmission away' from an unsafe situation. In the future I will be increasing my safety bubble while instructing so as to take action with enough time to absorb a missed transmission or read back.
SCT Controller reported C340 entered a higher Minimum Vectoring Altitude.