An investigation into the aerodynamic and operational bottlenecks that define global aviation throughput.
Featuring deep-dives into Mumbai's extreme optimization and SFO's paired approach technology.
Comparing peak hourly sustained movement rates (Arr+Dep) on constrained runway configurations.
* Comparison of "Constrained Operations": Included are single runways (LGW, BOM, SAN, old SZX) and dependent parallel runways (SFO in IMC).
Every aircraft generates powerful counter-rotating vortices from its wingtips—essentially horizontal tornadoes that can flip a smaller trailing aircraft. This is not a bureaucratic rule; it is physics.
To survive, a Medium aircraft (like A320) must stay 5 nautical miles behind a Heavy (like B777). At approach speeds, this creates a mandatory time gap of ~2 minutes where the runway sits empty. Capacity is purely a function of how fast these vortices dissipate.
Traditional categories (Heavy/Medium/Light) were too broad. New "Recategorization" standards split aircraft into 6+ tiers (e.g., 'Upper Heavy', 'Lower Heavy'), allowing controllers to safely shave off 0.5-1.0 NM separation in specific pairs, boosting capacity by 5-10%.
ROT is the stopwatch measurement from the moment an aircraft crosses the landing threshold until its tail completely clears the runway line.
A trailing aircraft cannot be cleared to land (or in some regulations, cross the threshold) until the runway is clear. High ROT is a capacity killer. If pilots miss a "High Speed Exit" and have to taxi to the end, a 50-second routine turns into a 90-second delay, forcing the next arrival to go around.
Airports like Mumbai and Gatwick design "Rapid Exit Taxiways" (RETs) angled at 30 degrees, allowing planes to turn off at 50 knots (93 km/h). Standard 90-degree exits require slowing to 10 knots, adding 20+ seconds to ROT.
Archived report. Check the original dates, sources and forecast assumptions before using figures.
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