What Is Computer-Aided Design and Why It Matters for Landing Gear

Landing gear is among the most critical systems on any aircraft. It must absorb enormous impact forces during touchdown, support the full weight of the aircraft on the ground, and retract seamlessly into the fuselage during flight. Designing such a complex, high-stress assembly demands extreme precision. Computer-Aided Design (CAD) has become the cornerstone of modern landing gear engineering, replacing manual drafting with powerful digital tools that allow engineers to model, simulate, and refine every component before a single piece of metal is cut.

CAD software enables the creation of three-dimensional, parametric models of landing gear parts—shock struts, torque links, wheels, brakes, retraction actuators, and control valves. These models are not just static images; they contain embedded data about material properties, tolerances, and assembly relationships. This digital foundation supports everything from initial concept studies to detailed manufacturing drawings. In aerospace, where safety margins are razor-thin and failure is not an option, CAD is indispensable.

How CAD Is Applied to Landing Gear Design

3D Modeling of Complex Assemblies

Landing gear consists of dozens of interconnected components that must move in precise coordination. With CAD, engineers build full 3D assemblies that can be rotated, exploded, and examined from any angle. This visibility helps identify interferences—for example, a hydraulic line rubbing against a moving link—long before physical prototypes are built. Modern CAD platforms such as Autodesk Fusion 360 and Siemens NX offer specialized aerospace toolkits that include libraries of standard fasteners, material databases, and simulation interfaces.

Kinematic Analysis

Landing gear must extend and retract reliably under aerodynamic loads. Engineers use CAD to define kinematic relationships between links, actuators, and pivot points. By animating the retraction sequence within the software, they can verify that the gear clears surrounding structures like wheel wells and doors. This virtual testing eliminates trial-and-error and reduces the risk of jams or binding in operation.

Integration With Finite Element Analysis (FEA)

CAD models serve as the geometry input for FEA, which calculates stresses, strains, and deformations under static and dynamic loads. Landing gear components experience extreme forces—multiaxial bending, torsion, and impact. Engineers assign material properties to the CAD model, apply boundary conditions simulating landing impacts, and run simulations to identify weak points. The immediate feedback loop between CAD and FEA allows rapid design iterations to optimize strength and weight.

The Tangible Benefits of CAD in Landing Gear Engineering

Unmatched Precision and Accuracy

Manual drafting introduces inevitable human errors—misaligned dimensions, overlooked tolerances, or mismatched hole patterns. CAD enforces geometric constraints and parametric relationships so that changing one dimension automatically updates all dependent features. This ensures that every part in the assembly mates correctly. For landing gear, where a clearance of a few thousandths of an inch can mean the difference between smooth operation and catastrophic failure, this precision is non-negotiable.

Dramatic Cost and Time Savings

Building physical prototypes of landing gear is extremely expensive. Each test article requires machining, heat treatment, surface finishing, and assembly. With CAD, engineers can perform virtual fit-checks, motion studies, and even preliminary load calculations without producing any hardware. This reduces the number of physical prototypes needed and shortens development cycles from years to months. One major landing gear manufacturer reported a 40% reduction in time-to-market after fully adopting an integrated CAD-CAE workflow.

Realistic Simulation and Virtual Testing

Modern CAD platforms include built-in simulation tools or integrate seamlessly with dedicated solvers. Engineers can simulate:

  • Landing impact: Apply vertical and horizontal velocities at the tire contact patch to see how the shock absorber strokes and how loads distribute through the structure.
  • Retraction and extension: Model actuator forces, friction, and aerodynamic drag to ensure the mechanism operates reliably at all airspeeds.
  • Thermal effects: Braking generates intense heat; CAD-based thermal simulation helps design cooling paths and select materials that withstand high temperatures.
  • Fatigue life: Using simulated stress histories, engineers predict crack initiation and propagation, allowing them to add reinforcements precisely where needed.

This level of analysis builds confidence in the design and uncovers issues that would only appear after costly field failures.

Iterative Design Optimization

Landing gear components must be as light as possible to improve aircraft fuel efficiency, yet strong enough to survive repeated hard landings. CAD supports generative design and topology optimization, where the software suggests material layouts that minimize weight while meeting strength constraints. Engineers can explore hundreds of candidate geometries in a fraction of the time it would take to model each manually. The result is innovative shapes—often organic-looking lattices—that would be impossible to draft by hand.

Impact on Safety and Innovation

Thorough Up-Front Analysis Prevents Failures

CAD enables engineers to perform failure mode and effects analysis (FMEA) virtually. By simulating overload scenarios—such as a hard landing or a tire blowout—they can verify that the gear retains structural integrity and that backup systems activate correctly. For example, the Boeing 787 landing gear design used extensive CAD and simulation to optimize the twin-post configuration, reducing known failure modes from earlier models. The ability to test “what if” conditions safely on a computer has directly contributed to the industry’s improving safety record.

Fostering Material and Design Innovation

CAD removes the constraints of manual drafting, allowing engineers to experiment with advanced materials like carbon-fiber composites, titanium alloys, and high-strength aluminum-lithium. These materials behave differently than traditional steel; CAD models capture anisotropic properties, ply orientations, and layer stacking. Engineers can simulate how a composite torque link deforms under load and adjust the layup to maximize strength. This freedom has led to landing gear designs that are up to 20% lighter than their metal predecessors while maintaining or exceeding durability.

Real-World Example: Landing Gear for Regional Jets

A leading landing gear manufacturer, Safran Landing Systems, uses CAD extensively to develop gear for aircraft like the Embraer E-Jets E2. Their engineers create full digital twins of the landing gear, including hydraulics, electronics, and mechanical linkages. These digital twins are used throughout the product lifecycle—from concept to maintenance—allowing teams around the world to collaborate on design improvements. The result is higher reliability and faster troubleshooting when issues arise in service.

Integration With Complementary Technologies

CAD does not work in isolation. Its full potential is realized when integrated with other engineering tools:

  • Computational Fluid Dynamics (CFD): Landing gear creates significant drag. CAD models are exported to CFD solvers to study airflow around extended gear, leading to fairings and streamlined shapes that reduce fuel burn.
  • Computational Structural Mechanics (CSM): For detailed stress analysis beyond basic FEA, CAD geometry feeds into advanced CSM solvers that model nonlinear behavior, contact, and large deformations during landing impact.
  • Product Lifecycle Management (PLM): CAD data is managed within PLM systems that track revisions, approvals, and compliance with regulatory standards like 14 CFR Part 25. This ensures every change is documented and traceable.
  • Additive Manufacturing (3D Printing): CAD enables the design of complex, lightweight geometries that can only be produced through additive manufacturing. Examples include intricate hydraulic manifolds and custom brackets that consolidate multiple parts into one.

Artificial Intelligence and Machine Learning

AI is beginning to augment CAD by automating routine tasks—such as generating draft views, checking for design-rule violations, and even proposing alternative configurations. Machine learning algorithms trained on thousands of previous landing gear designs can predict which geometries will perform best under given loads, accelerating the optimization process. Soon, engineers may simply input performance requirements, and AI will generate a family of CAD models ready for analysis.

Digital Twins and Continuous Simulation

The concept of a “digital twin” extends the CAD model beyond design into production and service. Sensors on landing gear during flight transmit real-time data (loads, temperatures, wear) back to the digital twin, which updates its predictions for remaining fatigue life. This allows airlines and maintenance teams to schedule repairs proactively rather than reactively. CAD is the foundational geometry for these twins; without an accurate, up-to-date CAD model, the twin cannot provide reliable insights.

Cloud-Based Collaboration and Real-Time Co-Design

Cloud platforms like Onshape allow multiple engineers—often in different countries—to work on the same landing gear model simultaneously. Changes appear instantly, and version control is automatic. This is a game-changer for large aerospace programs where airframers, gear suppliers, and regulators must coordinate closely.

Generative Design and Additive Manufacturing Convergence

Generative design algorithms within CAD software explore thousands of load paths to produce weight-optimized structures. When combined with metal 3D printing, these designs become manufacturable. Landing gear brackets that previously required welding and machining from solid stock can now be printed as single, monolithic parts with internal lattice structures. The result is a part that is 40% lighter and equally strong. As additive manufacturing scales up, CAD will need to handle larger builds and more complex support structures.

Conclusion

Computer-Aided Design has transformed landing gear engineering from a discipline of manual drafting and costly physical prototyping into a digital, simulation-driven science. The ability to create precise 3D models, simulate extreme loads, iterate rapidly, and integrate with analysis tools has made landing gear safer, lighter, and more reliable. As AI, digital twins, and additive manufacturing continue to advance, CAD will remain the central platform where ideas become tangible—and where the next generation of landing gear is born. For engineers and manufacturers committed to pushing the boundaries of aerospace performance, investing in CAD capability is not optional; it is essential.