What is MR on Boeing 737? (Modification Revision)

Boeing 737, one of the most popular and widely used aircraft in the world, has undergone various modifications and revisions throughout its long history. These modifications, often referred to as Modification Revisions or MRs, play a crucial role in improving the aircraft’s performance, safety, and efficiency. In this article, we will explore what Modification Revision entails, its significance, and some notable MRs that have been implemented on the Boeing 737.

The Significance of Modification Revision

Modification Revision, as the name suggests, involves making changes and improvements to the original design of the Boeing 737. These modifications can be minor adjustments or major updates, aimed at enhancing various aspects of the aircraft’s functionality.

The primary goal of Modification Revision is to ensure that the Boeing 737 remains a state-of-the-art aircraft by incorporating the latest technological advancements and addressing any issues discovered during its operational life. It allows Boeing to stay ahead of the curve and adapt to changing regulatory requirements, industry standards, and customer expectations.

Additionally, Modification Revision enables Boeing to introduce new features and options that enhance passengers’ comfort and convenience while also providing operators with cost-saving measures. By continuously improving the aircraft, Boeing can extend its service life, increase its operational flexibility, and maintain its competitive edge in the aviation industry.

Notable Modification Revisions on Boeing 737

Over the years, numerous Modification Revisions have been implemented on the Boeing 737, each addressing specific areas for improvement. Let’s take a closer look at some notable MRs:


The Modification Revision 2 (MR-2) was introduced in the late 1960s as an upgrade to the original Boeing 737-100 and 737-200 models. MR-2 involved a series of changes, including an increase in maximum takeoff weight, improved aerodynamics, and upgraded engines. These enhancements resulted in improved fuel efficiency, increased range, and higher payload capacity, further solidifying the Boeing 737’s position as a versatile and economical aircraft.

With MR-2, Boeing addressed several technical challenges and incorporated improvements based on customer feedback. The newly introduced Pratt & Whitney JT8D-9 engines provided better performance, and the increased takeoff weight allowed operators to carry more passengers and cargo without compromising safety.


Following the success of MR-2, Boeing introduced the Modification Revision 3 (MR-3) in the 1980s. MR-3 mainly focused on upgraded avionics systems and introduced the Electronic Flight Instrument System (EFIS), replacing traditional analog cockpit instruments with digital displays. This change not only enhanced situational awareness for pilots but also reduced workload and increased aircraft reliability.

The EFIS provided pilots with a more intuitive and comprehensive display of critical flight information, such as altitude, airspeed, and navigation data. This technology leap represented a significant advancement in aviation, setting the stage for future cockpit innovations.


One of the most notable Modification Revisions in recent years is MR-9, which was introduced in the mid-2000s. MR-9 focused on improving the Boeing 737’s fuel efficiency, reducing emissions, and enhancing overall performance.

An essential aspect of MR-9 was the incorporation of advanced winglets, installed at the tips of the wings. These winglets, inspired by the design of bird wings, effectively reduced drag and improved aerodynamics, resulting in significant fuel savings and increased range.

According to Boeing, the installation of winglets on the Boeing 737-800, one of the most widely used variants, resulted in a 4% reduction in fuel consumption. This reduction not only translates to lower operating costs for airlines but also contributes to a greener and more sustainable aviation industry.

Overall, MR-9 showcased Boeing’s commitment to continually enhance the performance and efficiency of the Boeing 737, making it an even more attractive choice for airlines worldwide.


Modification Revision has played a vital role in improving the Boeing 737 throughout its long-standing history as a leader in commercial aviation. With each MR, Boeing has addressed key areas for enhancement, incorporating technological advancements and customer feedback.

The Modification Revisions, such as MR-2, MR-3, and MR-9, have significantly contributed to the Boeing 737’s success by improving fuel efficiency, increasing payload capacity, enhancing avionics systems, and reducing emissions. These MRs ensure that the Boeing 737 remains a competitive and reliable choice for airlines, benefiting both operators and passengers alike.

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