Principal Mechanical Process Engineer

Location: Barrow-in-Furness. We offer a range of hybrid and flexible working arrangements – please speak to your recruiter about the options for this role.

Salary: Circa £55,000

What you’ll be doing:

• Lead the end-to-end development of complex fluid systems, shaping designs that meet demanding performance and environmental requirements.
• Create and review high-value engineering deliverables – for schematics and P&IDs to calculations, system descriptions, and 3D models.
• Drive advanced system analyses, including flow, pressure, thermal, and transient modelling to validate performance under challenging conditions.
• Select and assess critical equipment (pumps, compressors, valves, heat exchangers, filters, tanks), ensuring it meets tough submarine operating environments.
• Champion technology integrity by reviewing supplier documentation, ensuring full compliance with shock, vibration, atmosphere, temperature, maintainability, and access constraints.
• Influence design quality and safety, contributing to reviews, hazard studies, verification activities, and resolution of technical issues, modifications, and non-conformances.

Your skills and experiences:

Essential:

• Educated to degree level, with Chartered Engineer status highly desirable.
• Solid background in mechanical, marine, process, or fluid systems engineering gained with a complex or highly regulated environment.
• Strong knowledge of fluid dynamics, thermodynamics, pressure-drop behaviour, transient analysis, and system performance modelling.
• Demonstrated technical expertise in the design, analysis, and integration of both compressible and incompressible fluid systems.

Desirable:

• Experience using industry-standard modelling and analysis tools such as FloMASTER, FluidFlow, MATLAB, CFD packages, ANSYS, or similar.

Benefits:

As well as a competitive pension scheme, BAE Systems also offers employee share plans, an extensive range of flexible discounted health, wellbeing and lifestyle benefits, including a green car scheme, private health plans and shopping discounts – you may also be eligible for an annual incentive.

The Mechanical Engineering Discipline team:

This is an exciting opportunity to join the SSN AUKUS Platform Mechanical Integrated Delivery Team as a Principal Mechanical Design Engineer, where you’ll serve as a technical specialist for some of the submarine’s most critical compressible and incompressible fluid systems. In this role, you’ll take ownership of high-integrity mechanical designs that must perform flawlessly within one of the most demanding engineering environments in the world. You’ll shape complex system solutions, influence platform-level decisions, and ensure designs meet the rigorous performance, safety, and environmental requirements unique to submarine engineering. This is a chance to work at the forefront of next-generation naval capability, tackling challenging technical problems and contributing directly to one of the UK’s most advanced defence programmes. We offer relocation support across all Submarine roles, subject to meeting eligibility criteria.

Why BAE Systems?

This is a place where you’ll be able to make a real difference. You’ll be part of an inclusive culture that values diversity of thought, rewards integrity, and merit, and where you’ll be empowered to fulfil your potential. We welcome people from all backgrounds and want to make sure that our recruitment processes are as inclusive as possible. If you have a disability or health condition (for example dyslexia, autism, an anxiety disorder, etc.) that may affect your performance in certain assessment types, please speak to your recruiter about potential reasonable adjustments.

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.

Closing Date: 30th January 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.