Principal Systems Engineer - Defence

Engage in the early definition and development of complex Command & Control systems with ALTEN Ltd. Join our team as a Principal Systems Engineer, working at the very front end of the engineering lifecycle to define architectures, requirements and concepts from first principles. You’ll operate within uncertain and evolving domains, shaping system solutions for complex aerospace, land and maritime environments, while providing technical leadership and guidance across multidisciplinary engineering teams.

Location: Berkshire
On‑site: Hybrid, 3 days per week
Seniority: Principal
Security Clearance: Candidates must be willing and eligible to obtain SC clearance.

Key Responsibilities

• Lead systems engineering activities across the full lifecycle, with strong focus on concept and early definition phases
• Define and develop system requirements and architectures within complex, evolving environments
• Conduct architecture and design trade studies, documenting options, risks and recommendations
• Scope and plan engineering activities across the full product lifecycle
• Produce high‑quality technical documentation and reports to support decision‑making
• Apply strong understanding of military communication systems and heterogeneous networks
• Perform system modelling using tools such as Enterprise Architect or Cameo
• Support networking and security function definition at system and sub‑system level
• Provide technical leadership, coaching and mentoring to less experienced engineers

Required Skills

• Significant experience as a Systems Engineering practitioner
• Strong background in early‑stage concept development and architecture definition
• Proven ability to define and manage system and sub‑system requirements
• Experience performing architecture trade studies and technical assessments
• Knowledge of military and civil aerospace systems and environments
• Experience with system modelling tools (Enterprise Architect, Cameo or similar)

Soft Skills & Collaboration

• Strong stakeholder engagement and customer‑facing capability
• Confident technical communicator with strong coaching ability
• Comfortable working under pressure in complex programmes
• Sound judgement when balancing technical requirements, cost, risk and constraints
• Collaborative mindset with the ability to influence across disciplines

Required Qualifications:

• Bachelor’s or Master’s degree in Engineering, or relevant technical military background with equivalent experience.

Desirable Skills

• Experience across airborne, land and maritime systems
• Knowledge of open/reference architectures (MOSA, SOSA, Pyramid, MDIS)
• Background in C2 or information management systems
• Understanding of communications systems, datalinks and networks (e.g. Link 16)
• Exposure to autonomy, networking or cloud‑based/micro‑services architectures

Why join us? 

We bring together entrepreneurial, tech-driven people to deliver innovative solutions for leading companies.

At ALTEN, you’ll work on exciting projects, supported by ongoing learning, mentoring, and clear career development tailored to your goals.

Join a passionate team and help build tomorrow, today.

In short you get: 

• A personalised career path and a rewarding management style 
• A huge diversity of engineering projects and industries
• Private Medical Insurance
• Cycle & Tech Scheme 
• Employee assistance programme
• Life insurance & Pension Scheme
• Social atmosphere, regular gatherings & team buildings
• Flexible way of working (role dependent)

We are proud to support the Armed Forces Covenant & actively encourage applications from members of the Armed Forces community, including veterans, reservists, service leavers, and military spouses/partners. We recognise the value of military skills and experience and are committed to ensuring that no applicant is unfairly disadvantaged during our recruitment and selection processes. 

ALTEN is committed to fostering a diverse and inclusive workplace and values the strength that comes from a global mix of backgrounds and perspectives. We welcome applications from all suitably qualified candidates, regardless of background or protected characteristics under the Equality Act 2010. If you require any reasonable adjustments during the recruitment process, please let us know. 

This role may require you to have or be willing to go through Security Clearance. As part of the onboarding process candidates will be asked to complete a Baseline Personnel Security Standard; details of the evidence required to apply may be found on the government website Gov.UK. If you are unable to meet this and any associated criteria, then your employment may be delayed, or rejected . Details of this will be discussed with you at interview.