Airport Runway Operations: How Planes Take Off and Land

Runway Selection: Wind, Weight, and Configuration

The selection of which runway to use for a given operation is one of the most consequential decisions in airport operations. The primary driver is wind: aircraft generate lift relative to the air passing over their wings, not relative to the ground. Taking off into a headwind means the aircraft reaches flying speed (lift exceeds weight) at a lower ground speed, shortening the required runway length. A 20-knot headwind component effectively reduces the ground speed needed for rotation by 20 knots, translating to a meaningfully shorter takeoff roll and better performance margins. For this reason, controllers almost always assign the runway most closely aligned with the current wind direction.

Runway configuration at multi-runway airports involves more complex trade-offs. Parallel runways can handle simultaneous operations — one for arrivals, one for departures, dramatically increasing throughput. Closely-spaced parallel runways (less than 760 meters apart, as at Los Angeles International) require staggered approaches rather than simultaneous independent approaches, limiting the efficiency gain. Widely-spaced parallel runways (over 1,310 meters apart, as at Dallas/Fort Worth's east and west runway complexes) allow fully independent simultaneous approaches, each effectively operating as a separate runway system.

Noise abatement procedures add another dimension to runway selection. Many airports operate preferential runway systems — configurations that route departure and arrival paths away from densely populated areas, even if wind conditions would permit other configurations. At Sydney Airport (SYD), community agreements mandate a curfew on certain runway operations at night and require specific departure tracks during morning hours to minimize noise over residential areas to the east. At London Heathrow, an alternation scheme alternates westerly operations between the north and south runways on a daily basis, giving communities on each side a few hours of relative quiet each day.

The Takeoff Roll: From Brakes Release to Liftoff

A commercial aircraft takeoff is a precisely calculated event governed by three critical speeds: V1 (decision speed), Vr (rotation speed), and V2 (takeoff safety speed). Before the takeoff roll begins, the flight crew consults performance tables incorporating aircraft weight, runway length, gradient, elevation, temperature, wind, and surface condition to determine these speeds. The calculations ensure that if an engine fails at or before V1, the aircraft can either stop safely within the remaining runway, or continue the takeoff and climb away safely — whichever the performance data supports.

At V1 — typically 130–155 knots for large jets — the captain's hand leaves the thrust levers. Beyond V1, stopping is no longer a viable option even with maximum braking; the aircraft will run off the end of the runway. At Vr, the pilot applies back pressure on the controls (or sidestick on fly-by-wire aircraft), rotating the nose to a pitch attitude of approximately 10–15 degrees, increasing the angle of attack until the wings generate enough lift to become airborne. V2, typically 10–15 knots above Vr, is the target speed for the initial climb segment — the minimum speed that ensures safe climb performance with one engine inoperative.

Thrust settings for takeoff are carefully managed. Modern engines can generate more thrust than most runways and aircraft structures require, and running at maximum thrust causes faster wear and higher maintenance costs. Airlines frequently use derated or assumed temperature thrust, where the engines are set to produce less than their maximum rated thrust for a given runway condition. If the runway is long enough and conditions allow, a 10–20% thrust derate can significantly extend engine life at very modest cost in runway usage. Only when performance requirements are tight — short runway, high altitude, hot day, heavy weight — do airlines use full thrust.

Instrument Landing Systems: Precision Approaches

The Instrument Landing System (ILS) is the primary precision approach navigation aid used at commercial airports worldwide. It consists of two radio beams transmitted from the airport: the localizer (broadcasts along the runway centerline extended, operating at 108–112 MHz) and the glide slope (broadcasts the 3-degree descent path to the runway, operating at 329–335 MHz). Aircraft ILS receivers decode these signals to display lateral and vertical guidance — needles that the pilot keeps centered to track the approach path precisely.

ILS is certified in three categories that correspond to the minimum visibility required to use them. CAT I requires runway visual range (RVR) of at least 550 meters and a decision height of 200 feet — the pilot must see the runway environment by 200 feet above the ground to continue landing. CAT II reduces these minimums to 300 meters RVR and 100-foot decision height. CAT III operations (A, B, and C) allow landings in RVR as low as 75 meters (Cat IIIB) or zero (Cat IIIC with no decision height). Full Cat III requires special aircraft avionics, special pilot training and currency requirements, special runway lighting and monitoring systems, and protected critical areas around the ILS antennas to prevent signal distortion.

Modern airports increasingly supplement ILS with RNAV/RNP approaches (Required Navigation Performance), which use GPS and onboard flight management systems to fly curved approach paths not possible with the straight ILS beams. RNP AR (Authorization Required) approaches can follow precise curved paths around terrain or into confined airports, enabling service to challenging locations. Innsbruck Airport in Austria uses RNP AR approaches to thread between Alpine peaks that would otherwise make the airport impossible to serve in low visibility. The Boeing 787 and Airbus A350 have particularly capable RNP systems that can achieve accuracy of 0.1 nautical miles laterally throughout the approach.

Visual Approaches and VFR Operations

In good weather, aircraft may be cleared for visual approaches — navigating to the runway using visual reference rather than ground-based navigation aids. Visual approaches are more flexible than instrument approaches, allowing controllers to position aircraft more efficiently by allowing them to fly direct to the runway rather than following prescribed instrument approach procedures. A controller might offer a visual approach to an aircraft 30 miles out, allowing it to cut directly to final rather than flying the full procedure turn or RNAV transition, saving 5–10 minutes of flying time per aircraft.

The visual approach slope indicator (VASI) and its more advanced version, the precision approach path indicator (PAPI), provide visual glidepath guidance to pilots on visual approaches. The PAPI, now standard at most commercial airports, consists of four lights mounted to the left of the runway threshold. When all four appear white, the aircraft is above the 3-degree glide path; when all four appear red, it is dangerously low. The standard indication for a correct 3-degree approach is two red lights (left) and two white lights (right). The PAPI is visible in daytime up to 5 miles and at night up to 20 miles, providing critical vertical guidance throughout the approach even without ILS.

Circling approaches present special challenges in operations. When an ILS or other approach procedure is aligned to a runway unsuitable for landing (perhaps due to wind), aircraft may fly an instrument approach to one runway and then circle visually to land on a different runway. Circling approaches have wider protected areas and higher minimums than straight-in approaches, and they require pilots to maintain visual contact with the airport throughout the maneuver. At airports surrounded by terrain or in mountainous areas, circling approaches may be restricted or prohibited for certain aircraft categories due to obstacle clearance concerns.

After Landing: Runway Exit and Taxiway Operations

After touchdown, exiting the runway as quickly as possible is critical to maintaining airport throughput. Each second an aircraft occupies an active runway is a second no other aircraft can use it for takeoff or landing. High-speed turnoffs — curved exits designed so aircraft can exit the runway at 60–90 knots without needing to brake to taxiway speeds first — are positioned approximately 900–1,800 meters from the runway threshold where most aircraft touch down and reach that speed after their initial braking. Airports like Amsterdam Schiphol and Frankfurt have invested heavily in high-speed turnoff infrastructure to maximize runway throughput.

After exiting the runway, aircraft receive taxi instructions from ground control. The tower controller hands the aircraft off to ground when it exits, and ground guides it to the assigned gate via a specific taxi route to avoid conflicts with other aircraft, vehicles, and pedestrians on the apron. At complex airports, taxiing from runway to gate can involve numerous intersections and turns. Frankfurt Airport issues paper taxi charts to flight crews showing the specific route, and many modern flight management systems include moving map displays with airport diagrams that highlight the aircraft's current position on the taxiway network.

Runway incursions — unauthorized entry onto an active runway — are among the most dangerous events in airport operations. The world's deadliest aviation accident (Tenerife, 1977, 583 fatalities) occurred when a KLM 747 started its takeoff roll while a Pan Am 747 was still on the runway in thick fog. Modern prevention measures include stop bar lights (red lights across taxiway-runway intersections that tower controllers can illuminate to prevent runway entry), runway guard lights (amber flashing lights on either side of a runway intersection warning of an active runway ahead), and surface surveillance systems that trigger controller alerts when aircraft enter a runway without clearance.