What is LCN in Aviation? (Load Classification Number)

In aviation, the Load Classification Number (LCN) plays a crucial role in determining the suitability of an airfield or runway for different types of aircraft and loads. LCN is a numerical value that indicates the strength of a runway pavement and its ability to withstand the weight and pressure of different aircraft operations. It is a standardized system used by aviation authorities around the world to classify and manage the load capacity of runways, ensuring safe and efficient operations.

Understanding Load Classification Number (LCN)

The Load Classification Number (LCN) is typically expressed as a three-digit value, such as LCN 30 or LCN 70. The first digit represents the load carrying capacity of the pavement, while the second and third digits indicate the strength of the runway under heavier loads. A higher LCN value signifies a stronger and more durable pavement capable of accommodating larger aircraft and heavier loads.

The LCN system takes into account various factors, including the thickness and composition of the pavement, its structural design, and the anticipated weight and distribution of loads. Different aircraft types have different LCN requirements based on their maximum takeoff weights, tire pressures, and landing gear configurations. Therefore, understanding the LCN of a runway is crucial for pilots, airfield managers, and aviation authorities to ensure the safe operation of aircraft.

How is Load Classification Number Calculated?

The Load Classification Number (LCN) is calculated through a systematic process involving the measurement of the pavement’s structural characteristics and assessing its ability to withstand loads. The process typically involves the following steps:

1. Pavement Evaluation: An assessment of the runway pavement’s condition, including its thickness, composition, and any signs of distress or deterioration, is conducted. This evaluation helps identify the pavement’s strength and potential weaknesses.

2. Load Testing: Load testing involves subjecting a section of the pavement to known loads, such as the weight of an aircraft or a heavy vehicle. The response of the pavement under these loads, including any deformation or cracking, is measured. Based on the results, the load capacity and overall strength of the pavement can be determined.

3. Data Analysis: The data collected from pavement evaluation and load testing is analyzed to determine the Load Classification Number (LCN). The LCN is calculated based on factors such as pavement thickness, load capacity, and the expected number of load repetitions over time.

4. LCN Assignment: Once the LCN is calculated, it is assigned to the runway or airfield. This information is crucial for pilots, ground handlers, and airfield operators as it helps them determine the appropriate aircraft operations and load restrictions.

Importance of Load Classification Number (LCN)

The Load Classification Number (LCN) plays a vital role in aviation as it ensures the safe and efficient operation of aircraft on runways. Some key reasons why LCN is important are:

1. Safety

The LCN helps in ensuring the safety of aircraft operations by providing information on the load capacity and strength of runways. By adhering to the LCN guidelines, pilots can make informed decisions about takeoff and landing distances, as well as the maximum weight an aircraft can safely carry. This information is critical to prevent runway failures, structural damage, and accidents due to excessive loads.

Further, LCN also helps airfield operators identify potential maintenance needs and prioritize necessary repairs or upgrades to ensure the continued safe operation of the runway.

2. Efficiency

Efficiency is another key aspect where LCN plays a significant role. By classifying runways based on their load capacity, LCN allows airfield managers to optimize aircraft operations. It enables them to determine the most suitable runways for different aircraft types, ensuring that the appropriate infrastructure is utilized for each operation. This, in turn, reduces delays, minimizes the risk of damage to the pavement, and enhances the overall efficiency of airfield operations.

Additionally, LCN provides valuable information for runway planning and construction. When designing new runways or rehabilitating existing ones, engineers can consider the anticipated load requirements and design pavements accordingly. This helps in reducing the long-term maintenance costs and ensures the longevity of the runway.

3. Compliance and Standardization

Standardization is crucial in aviation to ensure consistent and safe operations. The Load Classification Number (LCN) provides a standardized classification system that is recognized and used internationally. Pilots, airfield managers, and aviation authorities worldwide can rely on LCN values to assess the suitability of runways for specific aircraft types and loads.

This standardization promotes compliance with regulations and guidelines set by regulatory bodies, such as the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA). By adhering to LCN requirements, airfields can meet international safety standards and effectively manage the load capacity of their runways.

It’s important to note that while LCN provides valuable information for runway classification and planning, it should always be used in conjunction with other factors, such as weather conditions, aircraft performance, and pilot expertise, to ensure safe and efficient operations.


The Load Classification Number (LCN) is a critical component of aviation operations, allowing for the safe and efficient use of runways. By providing information on the load capacity and strength of pavements, LCN helps pilots, airfield operators, and aviation authorities make informed decisions about aircraft operations. It enhances the safety, efficiency, and standardization of airfield operations, while also promoting cost-effective maintenance and runway design. Understanding and applying the principles of LCN is essential to ensure the smooth and secure functioning of the aviation industry.

For More: What is FTL in Aviation? (Flight Time Limitations)