Formal Comment by Jeffrey Bogen: SAMP EIS Aircraft Fleet Mix Seat Estimates Assumptions Not Accurate Today

A Des Moines resident's formal comment on the Sea-Tac Airport Master Plan (SAMP) Environmental Impact Statement argues that the SAMP's aircraft seat capacity assumptions are now outdated, pointing to major 2026 fleet expansions by Alaska Airlines and Delta that include significantly more and larger widebody aircraft operating from SEA. The comment contends that because larger planes carry more passengers per flight, fewer total aircraft operations would be needed to reach the SAMP's 56 million passenger target, meaning the airport could handle projected growth with less noise impact than the SAMP currently estimates. The author presents revised seat-capacity scenarios suggesting the SAMP's low-growth assumption is internally inconsistent and that updated fleet data should be incorporated into the EIS before final conclusions are drawn.

Notes

Formal public comment filed 2026-05-28 by Jeffrey Bogen, Des Moines resident, on the SAMP Environmental Impact Statement (EIS) challenging the accuracy of the SAMP’s aircraft seat estimates and fleet mix assumptions for Seattle-Tacoma International Airport (Sea-Tac Airport / SEA). Argues that Alaska Airlines’ January 2026 order of 105 Boeing 737-10 narrowbodies and 17 Boeing 787 widebody jets, plus daily nonstop Tokyo Narita service, and Delta Air Lines’ A330-900 widebody additions (Rome, Barcelona, Taipei), 18-gate lease at Concourses A and B, and 60-aircraft Boeing 787-10 order materially change the fleet mix assumed in SAMP. Presents revised seat capacity scenarios (0.5%, 2%, 3.5% annual growth) showing SAMP’s 148-seat-per-departure baseline requires 757K annual operations to serve 56M passengers — exceeding the ~450K ops ceiling — while higher-seat scenarios (168–182 seats/dep) are internally consistent with the ops ceiling. Contends the SAMP’s ops and noise modeling is internally inconsistent and must be updated.

V V