Job Title: Principal Mechanical Engineer Location: Barrow-in-Furness, Hybrid We offer a range of hybrid and flexible working arrangements – please speak to your recruiter about the options for this particular role. Salary: Circa £55,000 depending on skills and experience Who we are: Join BAE Systems and you’ll be part of something bigger. As a valued member of our global colleague network, you’ll bring your unique skills and perspectives to help pioneer progress and protect what matters most. You’ll be trusted to play your part in delivering the advanced, technology-led defence, aerospace and security solutions of tomorrow, shaping a safer future for all of us. From the depths of the ocean to the far reaches of space, there’s no limit to where a career at BAE Systems could take you. What you will be doing: In this role, you will lead the design and development of mechanical systems for next-generation Royal Navy submarines, with a focus on air purification and atmosphere monitoring systems. You will undertake system-level design, modelling and analysis, and produce design documentation, verification and validation evidence, and safety justifications. Working collaboratively with suppliers and cross-functional teams, you will support specification, qualification, and procurement activities. You will also play a key role in driving engineering governance through design reviews and peer reviews, while providing technical leadership across the project lifecycle. Core duties: You will design platform systems, sub-systems, and equipment, ensuring alignment with programme requirements and engineering standards You will undertake functional design activities, including modelling, analysis, and system performance evaluation You will produce and maintain design documentation, verification and validation evidence, and safety justifications You will support supplier engagement, including specification, qualification, and procurement of components You will collaborate with stakeholders across multidisciplinary project teams to ensure successful delivery You will drive engineering governance through design reviews, peer reviews, and technical oversight Essential skills Degree-level qualification, Chartered Engineer status, or working towards professional accreditation Mechanical engineering background in rotating machinery, components, or fluid dynamics Knowledge of platform-level constraints such as noise, shock, or survivability Experience integrating purification systems with submarine life-support, HVAC, and emergency systems Experience in the design of gas scrubbing, filtration, and environmental control systems (e.g. CO₂ removal, O₂ generation, contaminant management ) within complex, safety-critical environments The Mechanical Engineering team: The Mechanical Engineering team plays a key role in the design and development of submarine systems, delivering innovative solutions across complex and safety-critical environments. As a Principal Mechanical Engineer, you will contribute to system-level design, provide technical leadership, and support the development of advanced air purification and atmosphere monitoring systems, helping to shape the future of submarine capability. A place where everyone can thrive: We’re committed to building an inclusive workplace where everyone feels valued and supported. We know that a diversity of backgrounds, perspectives and experiences strengthens our teams and is vital to the work we do. Please be aware that many roles at BAE Systems are subject to both security and export control restrictions. These restrictions mean that factors such as your nationality, any nationalities you may have previously held, and your place of birth can restrict the roles you are eligible to perform within the organisation. All applicants must as a minimum achieve Baseline Personnel Security Standard. Many roles also require higher levels of National Security Vetting where applicants must typically have 5 to 10 years of continuous residency in the UK depending on the vetting level required for the role, to allow for meaningful security vetting checks. Why BAE Systems? Here you’ll build a career with purpose and limitless possibilities. With lifelong learning and meaningful work, this is a place where you can grow your career with confidence and be empowered to be your best. You’ll be recognised for your contribution and enjoy rewards tailored to what’s most important to you and your family, supporting your financial and personal wellbeing as well as a balanced lifestyle. In an environment embracing sustainable ways of working and with a strong sense of shared purpose, our supportive culture is a place you can feel you belong and be proud of the difference you make. Closing Date: 15th April 2026 We reserve the right to close this vacancy early if we receive sufficient applications for the role. Therefore, if you are interested, please submit your application as early as possible. LI-KP1 LI-onsite