Brochure block speed is one of the most over-weighted numbers in aircraft selection. Range with realistic reserves and runway flexibility decide whether an airframe fits the mission — and whether you'll spend year three repositioning to make trips work.
The block-speed trap
A 460-knot light jet versus a 410-knot one saves 8 minutes on a 700‑nm leg. That difference disappears the first time you tanker fuel to make the second leg, or burn 25 minutes vectored at the destination. Speed matters at the fleet level, not at the trip level.
Range with IFR reserves — the only number that counts
Advertised range is high-altitude, no-wind, full-fuel, light-cabin. Knock 12-18% off for realistic headwinds, IFR reserves, and a passenger load. CompAeros mission scoring uses the de-rated number by default and shows the brochure number as a ceiling.
Runway pairs — not single runways
Buyers fixate on the longest runway in their mission. The constraint is the shortest pair of runways flown together — balanced field on a hot day at altitude, not paper takeoff distance. Runway flexibility is what makes a Pilatus PC-24 feel like a different airplane than a Phenom 300 even on identical missions.
How CompAeros weights fit
The mission-fit score combines: passengers and payload (constraint), range with reserves (constraint), runway-pair flexibility (constraint), avionics generation (compatibility), and total cost (preference). Constraints disqualify; preferences rank.
If your top-five shortlist all looks similar on paper, weight runway and range with reserves harder. The shortlist will collapse to two or three.