What is MC on Boeing 737? (Master Change)

Master Change (MC) is a critical concept in the aviation industry, particularly in relation to the Boeing 737 aircraft. MC refers to the process of implementing and managing modifications and updates to the aircraft. These modifications can be as small as software updates or as significant as structural changes. In any case, MC ensures that these changes are properly documented, approved, and implemented in a systematic and controlled manner.

MC plays a crucial role in ensuring the safety, reliability, and efficiency of the Boeing 737 fleet. With the continuous advancements in technology and ever-changing regulatory requirements, it is imperative for aircraft manufacturers to have a robust system in place to manage and control changes effectively. The MC process provides the necessary framework to handle modifications throughout the lifecycle of the aircraft.

The Importance of Master Change

Master Change is of paramount importance in the aviation industry, and particularly for the Boeing 737 aircraft, due to several key reasons.

The Need for Continuous Improvement

The aviation industry is constantly evolving, with new technologies, regulatory requirements, and industry best practices emerging regularly. The Master Change process ensures that the Boeing 737 remains up to date and compliant with the latest standards. By implementing and managing changes effectively, Boeing can incorporate improvements and enhancements to the aircraft that enhance safety, performance, and fuel efficiency.

For example, the introduction of new navigation systems, flight control software updates, or structural modifications can significantly improve the overall capabilities and reliability of the Boeing 737. These improvements are crucial for airlines, as they can contribute to increased operational efficiency and reduced maintenance costs over the lifetime of the aircraft.

Ensuring Safety and Compliance

Safety is the number one priority in the aviation industry, and the Master Change process plays a vital role in ensuring the safety of the Boeing 737. By carefully documenting and managing modifications, Boeing can assess the potential impact on aircraft systems, structures, and performance. This allows for thorough testing and validation before implementing the changes in the fleet.

Moreover, MC helps ensure compliance with regulatory requirements. Regulatory bodies such as the Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA) require detailed documentation and approval processes for any modifications made to aircraft. The MC process provides a structured approach to meet these requirements and maintain the airworthiness of the Boeing 737 fleet.

The Master Change Process

The Master Change process on the Boeing 737 involves several key steps to ensure that modifications are implemented smoothly and efficiently.

1. Change Identification and Analysis

The first step in the MC process is to identify the need for change and analyze its impact on the aircraft. This involves assessing the potential benefits, risks, and costs associated with the proposed modification. The changes can originate from various sources, such as airlines’ feedback, regulatory requirements, or technological advancements.

Boeing’s engineers and design teams evaluate the proposed changes and conduct thorough analysis to determine the technical feasibility, impact on systems, structures, and performance, and the overall compatibility with the existing configuration of the Boeing 737.

2. Design and Documentation

Once a change is approved, the design and documentation phase begins. The engineering teams at Boeing develop detailed plans, drawings, and engineering specifications for the modifications. These designs need to consider various factors, including safety, reliability, maintainability, and regulatory compliance.

The documentation prepared during this phase is crucial, as it serves as the basis for regulatory approval and subsequent implementation. It includes technical drawings, system specifications, installation instructions, and any other relevant information required for the modification.

3. Testing and Validation

Before implementing the changes in the fleet, rigorous testing and validation are conducted to ensure that the modifications perform as intended and do not introduce any adverse effects on the aircraft’s systems or structure.

This phase involves various levels of testing, ranging from simulation and laboratory testing to ground and flight testing. The results of these tests are carefully analyzed to verify the safety, performance, and reliability of the modifications.

Additionally, the testing phase includes assessing the compatibility of the modifications with existing systems and evaluating their interactions and interfaces. This helps identify any potential issues that may arise when the changes are implemented in the fleet.

4. Implementation and Certification

Once the modifications have been thoroughly tested and validated, they are ready for implementation. This phase involves installing the changes in the aircraft, following the detailed instructions and procedures outlined in the documentation prepared earlier.

The implementation process is carefully controlled to ensure that all relevant parties, such as maintenance personnel, pilots, and regulatory authorities, are notified and involved. Boeing provides comprehensive guidelines and training to facilitate the installation process and ensure that it is carried out correctly.


Master Change is an essential process for managing modifications and updates on the Boeing 737 aircraft. It enables Boeing to continuously improve the aircraft, ensure compliance with regulatory requirements, and enhance safety and performance.

By following a systematic and controlled approach, the Master Change process allows for the seamless incorporation of changes throughout the lifecycle of the Boeing 737, benefitting both airlines and passengers. The thorough analysis, design, documentation, testing, and implementation ensure that modifications are well-planned and effectively implemented, contributing to the overall success of the Boeing 737 fleet.

For More: What is AFM on Boeing 737? (Airplane Flight Manual)