The Boeing 737, with all its iterations and variants, has been flying around the world for many years. For a time, it was the best-selling aircraft until the Airbus A320 overtook it recently. One distinct feature you might notice about the Boeing 737 is that it sits low to the ground. If you compare a 737 and an A320 side by side, you’ll notice that the latter sits taller when on the ground.
This low-stance design aspect of the Boeing 737, deeply rooted in the aircraft’s history and functionality, plays a role in its operations and has influenced its evolution over the years.
Origins of the Low Stance
The 737 was initially conceived as a smaller aircraft, primarily serving regional routes. Its design included the original JT8D low-bypass turbofans, which fit snugly under the wings. This configuration allowed the aircraft to operate efficiently at smaller airports without the need for additional support equipment. The built-in air stairs and a cargo bay positioned low to the ground made it convenient for passengers to board and for ground workers to load and unload baggage without extra machinery.
Another benefit of the 737’s low height was the need for shorter and lighter landing gear. This design choice was partly influenced by the Boeing 727, which had tail-mounted engines and a lower ground profile. By keeping the 737 low, Boeing maintained some commonality with the 727. However, as the 737 evolved, it grew longer, was fitted with larger engines, and became capable of much longer flights.
In contrast, the Airbus A320, the 737’s main competitor, was designed from the outset to accommodate the larger family of CFM56 high-bypass engines. When the A320 entered the market, the advantages of the 737’s low height were less pronounced, especially as the 737 Classic version, powered by similar engines, had significantly evolved from its original design.
The Challenge of Altering the Landing Gear
One might wonder, why not just lengthen the landing gear? The main gear of the 737 retracts inwards between the wings, with the wheels resting in the lower fuselage. Lengthening the gear would require shifting the attachment points outward or reconfiguring the wheels to sit in tandem rather than side-by-side. Both options would lead to extensive and costly modifications, including a major wing redesign or relocating numerous systems. Boeing management, weighing the costs, opted for software solutions over these mechanical changes.
Will the 737’s design continue as is? Boeing faces the inevitability of producing a new narrowbody aircraft. The limitations of the 737’s decades-old design, coupled with the challenges encountered by the 737 MAX, suggest that a new iteration based on the original 1960s blueprint is unlikely. Future Boeing narrowbodies will probably feature increased ground clearance, aligning with modern aviation needs and technological advancements.
I hope this article helps you understand why the Boeing 737 sits low to the ground. It should also explain why the engines of the 737 classics, NGs, and MAXs have a flat bottom. Additionally, this information should give you a clue as to why the engines of the MAX are mounted higher and more forward of the wing, leading Boeing to create the controversial MCAS or Maneuvering Characteristics Augmentation System.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
