About the job
Quest Defense Systems & Solutions seeks a Principal Software Engineer - Test Systems for its Tucson, AZ facility. This is a full-time, onsite role with relocation assistance for qualified candidates.
Role overview
This senior engineering position centers on designing and developing software, automation tools, and hardware interfaces used in advanced aerospace and defense test systems. The work directly supports the validation of mission-critical products, spanning both engineering and production environments. Day-to-day, expect hands-on involvement with C++, C#, Python, Visual Studio, and a range of lab instrumentation. Collaboration across disciplines is essential, particularly when integrating systems, troubleshooting complex setups, and supporting key programs.
What you will do
- Lead teams in the development of test equipment for aerospace and defense applications
- Manage multiple tasks simultaneously in a production context
- Support planning around cost and schedule management
- Communicate project updates clearly to senior management
- Troubleshoot issues involving both software and test equipment
- Develop requirements for new software products
- Maintain strong written and interpersonal communication with Program Management
Who will thrive
This role fits experienced engineers who enjoy building software that interacts with real hardware and want to contribute to advanced defense technology. The position involves working in a fast-moving setting and making a direct impact on high-visibility projects.
Security and location requirements
- U. S. citizenship required
- Ability to obtain and maintain a Secret Clearance
- Onsite work in Tucson, AZ
- Relocation assistance available

