Lead Mechanical Engineer, Airframe

ABOUT POSEIDON AEROSPACE: Poseidon Aerospace is reimagining how the world moves goods. We build and operate full-size autonomous cargo aircraft - capable of carrying two tons of payload over a thousand nautical miles. From remote communities to contested logistics operations, our platforms unlock a new cost curve for air freight, making it faster, cheaper, and accessible anywhere it's needed. Headquartered in the San Francisco Bay Area with locations in Washington DC, Oregon, and Maine; we're building something consequential. ABOUT THE ROLE The Lead Mechanical Engineer will own the structural and mechanical design of major aircraft assemblies from concept through flight testing. This role is responsible for setting technical direction, leading design reviews, managing subsystem interfaces, and supporting other mechanical engineers. It is a hands-on engineering position that requires detailed involvement in CAD, analysis, manufacturing, assembly, and testing. RESPONSIBILITIES - Lead the design of primary aircraft structures, mechanisms, and major airframe assemblies - Develop composite and metallic structures, joints, interfaces, and mounting systems - Define structural load paths, design requirements, margins, and validation methods - Perform and review hand calculations and finite element analysis - Evaluate strength, stiffness, buckling, fatigue, vibration, and composite failure modes - Lead preliminary and critical design reviews - Own CAD assemblies, production drawings, bills of materials, tolerances, and design releases - Manage mechanical interfaces between the airframe, propulsion, avionics, flight controls, landing systems, and other subsystems - Design aircraft mechanisms, including control surfaces, doors, landing gear, actuation systems, and deployable systems - Work with manufacturing to develop tooling, assembly processes, inspection methods, and repair procedures - Plan and support component, structural, subsystem, and vehicle-level testing - Investigate failures, determine root causes, and implement corrective actions - Mentor mechanical engineers and review their design and analysis work - Support aircraft assembly, integration, ground testing, and flight testing REQUIRED QUALIFICATIONS - Degree in Mechanical Engineering, Aerospace Engineering, or a related field - 7 or more years of relevant mechanical, structural, or aerospace engineering experience - Experience designing primary aircraft structures or large composite airframes - Experience with bonded composite structures, sandwich panels, bonded inserts, and hybrid composite-metallic assemblies - Experience with aircraft mechanisms, actuation systems, control surfaces, doors, landing gear, or deployable systems - Knowledge of composite failure criteria, buckling, fatigue, vibration, modal analysis, or damage tolerance - Experience taking safety-critical hardware from concept through manufacturing and testing - Strong proficiency with CAD software such as Fusion, SolidWorks, CATIA, NX, or Creo - Strong proficiency with finite element analysis tools such as ANSYS, Nastran, Abaqus, Fusion Simulation, or similar - Ability to verify analysis using hand calculations and first-principles methods - Strong understanding of structural mechanics, load paths, joint design, material behavior, and mechanical failure modes - Experience applying GD&T and mechanical tolerancing to production drawings - Experience designing for manufacturing, assembly, inspection, maintenance, and repair - Experience leading technical reviews and making design decisions across multiple engineering teams - Comfortable working directly with aircraft hardware, prototypes, test fixtures, and shop tools PREFERRED QUALIFICATIONS - Experience designing structures for marine environments - Experience developing structural test plans, fixtures, instrumentation, and acceptance criteria - Familiarity with FAA certification, military airworthiness, or experimental flight-test programs - Proficiency with MATLAB or Python for engineering analysis - Experience with product lifecycle management and configuration control systems Candidates who are not yet qualified for a Lead position may apply to our Mechanical Engineer openings. WHAT YOU GET FROM US - Competitive salary and meaningful early-stage equity - Relocation support if applicable - Employee Health Benefit Plans - 6% Retirement matching - Flexible PTO - Free lunches, snacks, and a stocked fridge at our offices - AI tools and subscriptions