Mirny sits above one of the largest diamond mines on earth, a remote Siberian town where the permafrost runs deep and the runway has nowhere generous to end. It is not a forgiving place to discover a gap in crew capability.
Days after S7 Airlines restricted all landing duties to captains — removing first officers from the Pilot Flying seat on approach — a Boeing 737-800 overran the runway there. No causal link has been established. None needs to be for the structural argument to hold.
The policy inverts decades of CRM doctrine. Rotation-based Pilot Flying schedules — where captains and first officers alternate legs — weren't designed as an equity measure. They were engineered as a proficiency system. Post-Tenerife, as investigators reconstructed how authority gradients contributed to catastrophic outcomes, ICAO and regulators codified a deliberate answer: distribute decision-making, distribute practice, distribute currency across both seats.
On major carriers operating under standard SOPs, first officers perform roughly half of all landings. That cadence isn't administrative. Manual handling skill — flare timing, crosswind correction, energy management on short finals — degrades without repetition. Currency is perishable, and the approach phase is where its absence is most consequential. Boeing's own accident data consistently links runway overruns to manual handling degradation and pressure-moment decision failures.
By concentrating all landings with captains, S7 didn't reinforce its safety layer. It collapsed the redundancy that modern SOPs deliberately engineer in. A first officer restricted from landing is a first officer whose manual proficiency atrophies — and whose ability to intervene, take control, or execute a go-around under pressure quietly erodes with every leg they spend as a passive observer.
Mirny is a data point. The policy is the variable worth examining.