The fuselage is an aircraft's main body section. On the Boeing 787 this structure is formed from multiple barrel pieces rather than the traditional arrangement of smaller aluminum panels that must later be riveted or adhesively bonded together. These one-piece barrels are manufactured in Wichita, Kansas, by Spirit AeroSystems, the Boeing spin-off that also produces fuselages for the 737.
By weight the 787 fuselage is 50% composite, 20% aluminum, 15% titanium, 10% steel, and 5% other materials; by volume composites account for roughly 80%. Approximately 32,000 kg of carbon-fibre-reinforced plastic (CFRP) composites are used, a departure from earlier models whose skins were primarily sheet aluminum.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is the fuselage of a Boeing plane?
The fuselage of a Boeing plane is designed to accommodate the crew, passengers, and cargo. The cockpit is at the front of the fuselage, where the pilots sit. The fuselage is an aircraft's main body section, and it is the central portion of the body of an airplane. It holds all the pieces of an airplane together, and houses passengers, crew, and cargo. The shape of the fuselage is normally determined by the mission of the aircraft.
What is the fuselage design of a Boeing aircraft?
The fuselage of a Boeing aircraft has a double bubble design. The Boeing design has a fuselage whose diameter varies over the cabin section. The Boeing 787 fuselage design is distinctive for big one piece barrel sections built by pressure molding on female molds, with frame stiffened curved panels and inverted hat stringers inside to handle loads around doors and windows. The effect of two circles of different diameters makes the aircraft's skin curve inside the cabin and gives cargo hold below and passenger seating above. Jet fuselages make use of a streamlined shape to reduce drag and are carefully designed to be as aerodynamically efficient as possible.
What is the fuselage diameter of a Boeing aircraft?
The Boeing 737 and 727 fuselage has a diameter of around 148 inches (3.76 m), a dimension that has remained consistent throughout the aircraft's long history. This width allows six-abreast seating (three per side) and a single aisle when 18-inch coach-class seats are installed. Wide-body Boeing models are larger: the Boeing 777 fuselage diameter is 6.20 m (244 in), while the Boeing 747 fuselage diameter is 20 ft (about 6.1 m). The outer diameter of Boeing 747 and 777 is 20 ft.
What is the thickness of a Boeing fuselage?
The Boeing 757 fuselage must have a thickness of 0.039 in (0.99 mm). Boeing 747 skin is 1.8-2.2 mm (0.07-0.087 in), while the aluminum skin wrapped around most pressurized airframes is typically around a millimeter thick (0.039 in). Fuselage skin varies between about 2-4 mm (0.079-0.157 in) for pressurized aircraft.
What is the Boeing fuselage made of?
The Boeing 787 fuselage is built from carbon-fiber-reinforced polymer (CFRP) composites. Each aircraft carries 23 tons (50,706 lbs) of carbon fiber embedded in epoxy resin, giving the airframe about 32,000 kg (70,559 lbs) of CFRP and making it 50% composite by weight and 80% by volume. Tubular barrel segments are laid up as a carbon-fiber skin over an aluminum substructure. Metal bulkheads and joining plates are fitted at the joints, and the sections are riveted together during final assembly. By weight, the total material contents are 50% composite, 20% aluminum, 15% titanium, 10% steel, and 5% other materials.
Does Boeing use composite fuselage?
Yes, the Boeing uses a composite fuselage. The Boeing 787 Dreamliner became the first major commercial airplane to carry a fuselage built primarily from composite material. One-piece composite barrel sections replaced the multi-sheet aluminum assemblies once held together with fasteners. Those same barrel sections, together with composite wings, doors, tail surfaces and interior furnishings, bring the airframe to roughly 50% composite by weight and up to 80% composite by volume. With no findings of fatigue in full-scale testing, the material choice cut structural weight and extended range for the long-haul, wide-body twin-jet.
Although the 777 and 777X families retain aluminum fuselage skins, each new Boeing generation, including 787, continues to increase the percentage of composite material. Carbon-fiber-reinforced plastic, produced from bobbins of carbon fiber at facilities like Tacoma's Toray Composites plant, supplies 23 tons to each 787 and is now the leading material not only on the fuselage but across most other airframe components.
Upon encountering the 787 Dreamliner, I noted the fine, rivet-less surface which was starkly different from the rough and riveted planes I was previously familiar with. I learned that the smooth, rivet-less exterior was not built from conventional metal mixtures but used composite materials. A technician highlighted the benefits of a composite fuselage - decreased poundage for greater gas economy and resistance to rust.
Jim GoodrichPilot, Airplane Broker and Founder of Tsunami Air
What are the differences between the fuselages of a Boeing and Airbus?
The differences between the fuselages of a Boeing and Airbus are explained in the table below.
| Boeing | Airbus |
|---|---|
| Cross section is more oblong | Cross section is perfectly circular |
| The rudder has a triangular extension in the front bottom | The rudder does not have a triangular extension |
| Windows are more angular | Windows are rounder |
| Doors move crossway and the levers turn left to right | Doors run parallel to the fuselage and the lever moves bottom-up |
| Overhead bins are smaller | Overhead bins are larger |
| The wing strobe lights flash only once | The wing strobe lights flash twice in rapid succession |
| Does not emit a "dog bark" sound | Emits a dog bark sound due to PTU |
| Cockpit uses control column | Cockpit uses sidestick |
| Nose is sharper | Nose is rounder |
What are the specifications of the fuselage across the Boeing models?
The specifications of the fuselage across the Boeing models are explained below.
- Boeing 737 MAX: The fuselage has a diameter of around 148 inches. It has a higher nose, a re-sculpted tail cone, and slightly more aerodynamically refined contours. Larger round engines with serrated chevrons sit farther forward on the wing. The 737 MAX 8 has a longer fuselage than the MAX 7, and the MAX 9 and MAX 10 continue the stretch, identifiable by the longer window line and the number of exit doors along the fuselage.
- Boeing 737-500: The fuselage length is 1 foot 7 inches (48 cm) longer than 737-200. It accommodates up to 140 passengers.
- Boeing 737-400: The fuselage is stretched a further 10 feet (3.0 m) and houses 188 passengers. This model required a tail bumper and strengthened wing spar.
- Boeing 737-900: Has a stretched fuselage, almost as big as 757-200 and a longer window line compared to 737-700. The model required a strengthened wing spar due to stretch.
- Boeing 727: Differs in length only from 707 and has the same cross-section as 707.
- Boeing 787-10: Has a length of about 68.3 meters.
Who manufactures the fuselage for the Boeing models?
Spirit AeroSystems manufactures fuselage sections for Boeing 737, 747-8, 767, 777 and 787 aircraft. Spirit produces the forward fuselage section for 747-8 and builds nacelles, struts and wing leading edge. The manufacturer makes forward fuselage, nacelles and struts for Boeing 747-8, 777 and 777X. Spirit manufactures nose and forward-cabin sections for most Boeing jetliners.
Where is the Boeing fuselage factory located? The Spirit AeroSystems facility is located in Wichita, Kansas. The site produces approximately 70% of Boeing 737 aircraft. The factory in Wichita builds forward fuselage for Boeing 737 and has been a key site for over 50 years.
Spirit AeroSystems is the main collaborator for constructing fuselages for the 737. Boeing depends on this worldwide provider system, focusing its own assets on final installation, subsystems incorporation, and total project organization. This arrangement gives a complicated reciprocity: it can contribute economic and mutual expertise, yet it establishes weaknesses, as past output disruptions stemmed from fallouts at Spirit.
How does Boeing perform fuselage assembly?
During Boeing fuselage assembly, robots fasten the panels of the fuselage together with only minimal fixed tooling. Boeing uses autonomous robotic technology to assemble the mid-fuselage section of the 777. Fuselage automated upright build (FAUB) process builds major aluminum fuselage sections using pre-programmed guided robot pairs. Robots drill and fill more than approximately 60,000 fasteners that are today installed by hand. Determinant assembly that replaces fixed tooling improves workplace safety and increases product quality. Two side panels and the keel are set into assembly jigs. Jig segments are rotated up into the final position, and the fixture is disassembled and removed from the completed fuselage shell, where finished nose sections are moved by overhead crane and attached to the fuselage sections joined at assembly positions 1 and 2.
To move the sections, Boeing uses the modified 747 Dreamlifter to transport components between suppliers and Boeing. Spirit AeroSystems assembles major sections built around the world, and wide-body components travel in oversized intermodal containers when shipped by overseas subcontractors. Components for 747, 767 and 777 travel by rail in specially designed Skybox cars, and BNSF EMD GP 38-2 diesels move loaded coil cars, Skybox cars, fuselage bearing flatcars to the final assembly facility, where large sections are joined with fasteners to complete the fuselage.
I have witnessed the formation process of a Boeing fuselage. The procedure starts with big pre-fabricated cylinder segments arriving at the terminal fabrication line. Skilled workman and machine-controlled systems orient these components with exceptional forethought, achieving tolerances that look unfeasible on such a big edifice. Machine-controlled boring and riveting riveters journey along the creases, placing rivets with continual uniformity. These power tool borer openings and devices accomplish thousands of operations, guaranteeing the structural whole of the full aircraft. The first connection takes interim locks, assuring that everything is properly fitted before the installation. Once the leading components are matched, the emphasis changes to the lasting connecting procedure, and the frame's main construction begins to assume its form. This phase produces a sole unseamed tubular that must resist huge pressurization powers.
Jim GoodrichPilot, Airplane Broker and Founder of Tsunami Air
What caused the fuselage damage in Alaska Airlines 737-9 Max?
Boeing's supply-chain failures, design flaws, and quality-control issues led to the fuselage blowout of an Alaska Airlines 737-9 MAX at sixteen-thousand feet. A quality escape described by Boeing CEO Dave Calhoun left the door plug that fills an unused emergency exit without the bolts needed to hold it in place. The plug blew out, causing rapid decompression and scattering debris across a residential area in West Portland. Cold-bond adhesive used to transfer pressurization loads in fuselage lap splices is prone to disbonding, so lap splices were prone to develop multi-site damage that led to widespread fatigue damage. Fatigue cracks propagated from the spliced section of the aft pressure bulkhead's web and weakened the bulkhead. An improperly conducted repair in 1978 accelerated this cracking, and corrosion damage attributed to fluid contamination in the lower fuselage structure further reduced residual strength. Abnormal nose-wheel impacts and fan-cowl fragments striking the fuselage fractured the skin, buckled underlying stringers and frames, and separated a cabin window, partially ejecting a passenger. Primary damage inspected after these events consisted of total separation and loss of a major portion of the upper crown skin and other fuselage structure, extending about eighteen feet aft of the main cabin entrance door.
What caused the Boeing fuselage damage flaw? Design flaws included the cold-bond lap-splice design with adhesive-bonded hoop loads that concentrated stress around countersunk fastener holes, making the fuselage crown lap splice prone to multi-site damage. Aft pressure bulkhead web splices were designed without adequate regard for fatigue-crack initiation at points of greatest stress from operational loads, and the door-plug design, larger than the fuselage aperture and assembled from inside, relied on a natural wedging action instead of positive mechanical retention.
What caused the Boeing fuselage damage failure? Structural failures are triggered when fatigue, corrosion, or accidental damage grow beyond the limits that Boeing's damage-tolerance principles are intended to contain. Extensive corrosion damage in the lower fuselage structure, widespread fatigue damage in lap splices, and fatigue cracks propagating from the spliced section of the bulkhead web each reduced residual strength below that required to resist cabin pressurization loads, leading to rupture or blowout.
What caused the Boeing fuselage damage incident? The January-5 2024 incident occurred because a quality escape allowed the door plug to be installed without the necessary bolts. The plug blew out at sixteen-thousand feet. Earlier incidents, like the 1988 explosive decompression of a 737-297 and the Southwest Airlines Flight 1380 engine failure, were caused by poor maintenance, fatigue, and uncontained engine fragments that struck the fuselage, separated a cabin window, and partially ejected a passenger.
The overarching issue is the accumulation of flight cycles rather than flight hours, which steadily enlarges fatigue cracks in fuselage lap joints, bulkhead splices, and skin panels. Operators with inadequate inspection and maintenance programs miss early signs of multi-site damage, corrosion, or loose fasteners, allowing cracks to reach critical length before the next scheduled structural inspection. Damage-tolerance methods, mandated by civil regulations unless they impose unreasonable penalties, aim to guarantee that such damage is found and repaired before it compromises the fuselage.
Are there holes in Boeing fuselages?
Yes, Boeing fuselages contain thousands of drilled holes for fasteners, systems ports and maintenance access, but recent attention has centred on misdrilled and out-of-specification holes. Boeing's commercial chief Stan Deal confirmed that some fuselage holes were not drilled exactly to requirements. A Spirit AeroSystems employee, while the 737 MAX planes were making their way through the production process, alerted a manager that the holes were too close to the edge of the piece of metal in a window frame. This non-conformance prompted inspection of 47 fuselages, in which incorrectly drilled holes were found in 22, and led to the discovery of similar issues on 50 undelivered aircraft.
Beyond these production errors, 747 and 787 models display intentional fuselage openings. On the 747, the hole under the belly just before the pack inlet is the forward overboard valve, listed as V462 in the 747-400 System Schematic Manual, which opens automatically if airflow in the forward compartment is low. The right-side fuselage opening is the E/E compartment smoke override valve - valve V448.
Boeing separately discovered excessive gaps in 787 forward pressure bulkhead joints. The gaps exceeded FAA-approved design specifications that limit such gaps to 0.12 mm (0.0047 in). Although Boeing says these gaps are a conformance issue, not a safety concern, the FAA has proposed a directive to require inspections of Boeing 787 planes and recommended a one-time visual inspection of the forward pressure bulkhead during the heavy maintenance check that occurs every 12 years.
All 737s can continue operating safely while Boeing reworks about 50 undelivered jets to repair the faulty rivet holes, and the company supports the FAA making guidance for gap inspections mandatory.
