N405YK

This airframe, registered as N405YK, is a Boeing 737-436(SF) completed in 1991 with manufacturer serial number 25267. The airframe is listed as owned by NAS Aircraft Leasing Company (a corporate lessor) and carries a United States registration. The conversion to a freighter configuration, including installation of a main-deck cargo door and removal of passenger fittings, defines its current role in cargo operations. Notable registry actions include its change from passenger configuration to a dedicated freighter conversion and continued operation under a leasing ownership model.

The cabin of this specific 737-436(SF), N405YK, is a converted freighter layout with a main-deck cargo door and no passenger seating, configured to maximize main-deck pallet or bulk cargo capacity. Avionics and systems retain the baseline Boeing 737 Classic-era fitment typical of the -400 series, with updates dependent on specific operator modification records. Typical mission profiles for this airframe center on short- to medium-haul freight sectors within its roughly 2,060 nm range and cruise speed near 473 kts, operated from a U.S. base under leasing arrangements. Maintenance considerations for this converted airframe emphasize freighter structural checks around the cargo door cutout and reinforced floor zones, along with life-limited component tracking consistent with the CFM56-3C1 engine type.

The Boeing 737-400SF occupies a niche as a cost-effective, medium-capacity narrowbody freighter for routes where quick turnarounds and main-deck loading are prioritized. In the secondary market, buyers and lessors value airframes like N405YK for predictable short-to-medium range performance and parts commonality across the 737 Classic family, while competing options include purpose-built freighters and converted 737-300/800 derivatives. Resale and maintenance considerations hinge on airframe age (built 1991), remaining structural life, and the condition of the conversion and engines.