B737-700
Maintenance Powerplant; Maintenance Airframe
Time Pressure; Distraction; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors
I was the Aircraft Inspector on B737. The aircraft had hail strikes that required replacement of leading edge slats 5;6;7; and 8. I was assigned the post installation inspection of these slats. I witnessed the torque of the upstops but overlooked the inspection of the cotter pins.  I was later notified that the aircraft had gone through an inspection in PHX and QC had discovered the missing safety devices.
Inspector reported that a step was omitted that required inspection of the cotter keys on the up stop attach bolts after torque.