Avionics Test Engineer Torrance, CA Mechanical Engineering

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.

We are looking for an Avionics Test Engineer to architect and execute the full suite of hardware test capabilities needed to move our avionics and control systems from prototype to production. In this role, you will own test requirements, automated test equipment (ATE) development, integration, validation, and performance characterization across domains including power electronics, digital interfaces, RF assemblies, motion control, and flight avionics.

You will design fixtures, build automated test stations, support DVT and qualification, and define the test performance envelope for components, circuit cards, and integrated sub-systems. This role blends hands-on lab work with systems-level reasoning and close collaboration with electrical, controls, software, and mechanical engineering teams.

• Develop and execute test plans at component, subassembly, and integrated system levels
• Design and build test fixtures, HIL environments, and automated test rigs
• Validate hardware performance across electrical, digital, mechanical, and RF metrics
• Instrument and log tests to ensure precision and traceability
• Lead failure analysis and root-cause investigations
• Support hardware teams by feeding test results back into design cycles
• Drive qualification and environmental test campaigns (thermal, vibe, EMI)
• Deploy and validate automated test equipment for boards and sub-systems

• B.S./M.S. in Electrical, Mechanical, Mechatronics, Aerospace, or related
• Experience testing high-power subsystems, high-speed digital interfaces, actuators, or RF hardware
• Hands-on experience developing automated test equipment using instruments such as oscilloscopes, DMMs, power supplies, loads, switch matrices, network analyzers, etc.
• Familiarity with embedded control systems and interfaces (CAN, RS-422/485, SPI, Ethernet)
• Experience with instrumentation control and data acquisition (Python, C++, protobufs, scripting)
• Ability to work independently and lead cross-functional test integration

• Experience in RF testing fundamentals or more advanced knowledge of Radar architecture
• Experience with software development for test automation for digital, power, and RF electronics (Python preferred)
• Experience controlling test instrumentation using SCPI, VISA, or PyVISA commands
• Experience developing GUIs or dashboards
• Experience in writing custom scripts for data analysis & database creation
• Experience writing software for Environmental Chambers and/or RF Chambers
• Exposure to flight-like test environments, including environmental stress screening (ESS)
• Experience with fault injection, failure mode testing, and reliability qualification for mission-critical systems
• Working knowledge of C/C++ or Python for custom test tooling or embedded systems debugging
• Background supporting flight test or launch operations.

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply.

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law.

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact View email address on click.appcast.io. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law.

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation.

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.