Job description

Why Castelion, Why Now Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts. This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact. Senior Avionics Test Engineer We are looking for a Senior 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. Responsibilities • 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 Basic Qualifications • 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 Preferred Skills and Experience • 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. Other Duties 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. Benefits And Perks All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day. While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance. Affirmative Action/EEO Statement Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.

Requirements

Must-haves

Why Castelion, Why Now
This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact.
Senior Avionics Test Engineer
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 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

Nice-to-haves

Preferred Skills and Experience
Experience with software development for test automation for digital, power, and RF electronics (Python preferred)

Application prep

Use the role’s language and application details while tailoring your materials.

Keywords to mirror

python

Platform: manatal
Effort: medium

Benefits

Benefits detected in the listing.

Dental

Vision

Paid Time Off

Parental Leave