TORA – Takeoff Run Available in Airport Planning

Definition of TORA (Takeoff Run Available)

TORA (Takeoff Run Available) is a foundational concept in airport design, aircraft performance, and flight safety. It refers to the declared runway length that is available and suitable for the ground run of an aircraft during takeoff. Measured from the takeoff threshold—the point where the takeoff roll begins—to the end of the runway surface declared available for acceleration, TORA is not always the same as the physical length of the runway. Its value is established by airport authorities, taking into account factors such as safety zones, obstacles, and compliance with both national and international regulations.

TORA is defined by regulatory bodies like the Federal Aviation Administration (FAA), which describes it as “the runway length declared available and suitable for the ground run of an airplane taking off” (FAA AC 150/5300-13B), and by the International Civil Aviation Organization (ICAO) in Annex 14, Volume I. These definitions are crucial for pilots, airport planners, and safety regulators because TORA directly impacts aircraft performance limits, allowable takeoff weights, and overall operational capability at an airport.

TORA is published for each runway direction and is included in airport directories, approach charts, and operational documentation. It is essential for pre-flight planning, as pilots and dispatchers must ensure that the available TORA is sufficient for the aircraft’s takeoff performance under current conditions (e.g., runway surface, weather, wind, temperature, and weight). TORA’s calculation and publication are mandatory at all airports serving commercial air transport, in accordance with ICAO and FAA standards.

TORA may be reduced below the full runway length due to displaced thresholds, obstacles, construction, or to maintain regulated runway safety areas (RSA). These reductions are designed to ensure that aircraft will not face hazards or insufficient stopping distance in the event of an aborted takeoff or engine failure. Thus, TORA is more than an operational figure—it is a built-in safety margin that underpins airport infrastructure, flight operations, and ongoing airport assessments.

Declared Distances: Overview and Context

In airport operations, declared distances are central to runway usability, safety, and compliance. Airports supporting instrument operations or commercial air transport must publish four declared distances for each runway end:

• Takeoff Run Available (TORA)
• Takeoff Distance Available (TODA)
• Accelerate-Stop Distance Available (ASDA)
• Landing Distance Available (LDA)

These distances are defined and regularly reviewed to reflect changes in operational requirements, runway geometry, and environmental conditions. Declared distances account for obstacles, terrain, displaced thresholds, stopways, clearways, and regulatory safety margins, rather than relying solely on the physical runway length.

Declared distances are essential for flight planning and aircraft performance calculations. Pilots use them to determine if takeoff and landing can be conducted safely. For instance, a heavy aircraft on a hot day requires a longer takeoff run, which must fit within the available TORA. Operational restrictions, such as NOTAMs (Notices to Airmen), can also temporarily affect declared distances.

The ICAO’s Annex 14 outlines methodologies for determining declared distances, emphasizing safety, obstacle clearance, and consistent international standards. These values play a crucial role in airport management, certification, accident investigation, and infrastructure development.

TORA in Relation to Other Declared Distances

Understanding the relationship between TORA and other declared distances is fundamental to safe and efficient airport and aircraft operations. Each declared distance serves a specific purpose and is calculated according to different criteria:

Takeoff Distance Available (TODA)

TODA equals TORA plus any clearway beyond the runway’s end. The clearway is an obstacle-free area permitting continued airborne takeoff but not ground roll. While TODA may be longer than TORA, its extra length only applies after the aircraft has left the ground. In practice, many airports have little or no clearway, making TODA equal to TORA.

Accelerate-Stop Distance Available (ASDA)

ASDA is the declared length of runway plus any stopway (a load-bearing paved area beyond the runway for aborted takeoff stopping). ASDA is critical for safety, ensuring that an aircraft aborting takeoff at decision speed (V1) can stop safely within the declared distance. At some airports, ASDA may be less than TORA due to the need to maintain safety areas or land use restrictions.

Landing Distance Available (LDA)

LDA is the length of runway declared suitable for landing and rollout, starting at the landing threshold (which may be displaced) and extending to the runway end. LDA is often less than the physical runway length due to displaced thresholds or unsuitable surfaces beyond the threshold.

How TORA is Used in Airport Operations

Flight Planning and Aircraft Performance

Pilots and dispatchers rely on published TORA values to determine if the available runway length is adequate for safe takeoff at the planned aircraft weight and environmental conditions. TORA is a key input in flight management systems and performance software for calculating takeoff speeds (V1, VR, V2), engine settings, and flap configurations. If the required takeoff run exceeds TORA, the aircraft must reduce weight or delay departure.

TORA is also integral to balanced field length calculations, where the runway distance required for both continuing takeoff after engine failure and aborting takeoff is equal and must not exceed TORA, TODA, or ASDA.

Regulatory Compliance

TORA is a regulatory requirement for all commercial airports (FAA 14 CFR Part 139, ICAO Annex 14). Any changes to TORA, whether permanent (construction) or temporary (obstacles), must be published and communicated via NOTAMs. Operators cannot attempt takeoff if the required takeoff run exceeds TORA, ensuring compliance and safety.

Runway signage and markings indicate the start of the takeoff run, displaced thresholds, and declared distance limits, aiding pilot situational awareness.

Runway Design and Safety

TORA is central to runway design, extension, and safety assessments. Increasing TORA can enable operations by larger aircraft or at higher weights. Obstacles, terrain, and safety area requirements may restrict TORA. Displaced thresholds are frequently used to ensure obstacle clearance or accommodate pavement conditions, reducing available TORA for takeoff.

TORA also influences emergency planning, as it defines the distance available for aborting or continuing a takeoff safely.

Factors Influencing TORA Calculation

Runway Length and Configuration

The physical runway length is the starting point, but TORA may be less due to:

• Displaced thresholds (for obstacles or pavement)
• Temporary restrictions (construction, maintenance)
• Runway intersections (intersection departures)

Only the portion of the runway that is unobstructed and load-bearing is declared as TORA.

Runway Safety Area (RSA) and Protection Zones

The Runway Safety Area (RSA) is a cleared zone around the runway to minimize damage in runway excursions. If the runway encroaches on the RSA, available TORA is reduced to maintain safety. The Runway Protection Zone (RPZ) must remain clear of incompatible uses, and obstacles here can also reduce TORA.

Obstacles, Displaced Thresholds, and Environmental Factors

Obstacles—such as buildings or terrain—near the runway end can require a threshold displacement and reduction of TORA. Environmental conditions (wet/icy surface) do not affect published TORA but must be considered in performance calculations. Wind, runway slope, and elevation influence required takeoff distance, impacting the operational use of TORA.

Examples and Use Cases

Real-World TORA Variations

• Los Angeles International (LAX) Runway 6L-24R: Physical length: 11,600 ft; declared TORA: 10,600 ft; LDA: 10,000 ft due to displaced thresholds and safety zones.
• Teterboro (KTEB) Runway 01: Physical length: 7,000 ft; TORA: 7,000 ft; ASDA: 6,090 ft due to RPZ constraints—ASDA (not TORA) limits accelerate-stop performance.

Temporary construction and obstacles frequently reduce TORA at airports worldwide, communicated via NOTAMs and updated charts.

Balanced vs. Unbalanced Field Operations

In balanced field operations, required accelerate-go and accelerate-stop distances are equal and must not exceed TORA, TODA, or ASDA. In unbalanced field scenarios, one distance may be shorter, and the limiting value dictates maximum takeoff weight or may prohibit takeoff altogether.

Conclusion

TORA (Takeoff Run Available) is a central pillar of airport planning, aircraft performance, and air transport safety. Its determination involves engineering, regulatory, and operational considerations, ensuring that every takeoff is conducted with adequate margin for acceleration, abort, and obstacle clearance. Understanding TORA and its relationship with other declared distances is essential for pilots, airport planners, and regulators committed to safe and efficient flight operations.

For more information on TORA, declared distances, or to optimize your airport’s operational safety, contact our team or schedule a demo today.