Principal Software Engineer

AALTO; Farnborough; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Short-term incentive plan

25 days holiday

Private medical, dental & optical

Pension plan

Income protection & life assurance

Salary sacrifice scheme

Employee assistance programme

Perkbox discounts

Job summary

AALTO, based in Farnborough, is seeking a Principal Software Engineer to lead safety‑critical airborne software development. You will shape requirements, architecture and verification across the full lifecycle, collaborating with systems, hardware, and flight operations teams to deliver high‑integrity software.

The role emphasizes deep technical delivery, mentorship, and strong coding in C, C++ and Python within a demanding aerospace domain.

Qualifications

• Significant hands‑on software engineering experience, ideally around 10 years or more, with a strong background in embedded or real‑time systems.
• Experience taking airborne software through the full DO-178C lifecycle and supporting aircraft certification activities.
• Strong C programming skills, with practical experience in C++ and Python.
• Sound understanding of software architecture, design trade‑offs, debugging and verification in safety‑critical or highly regulated environments.
• Experience working with multidisciplinary engineering teams and translating complex technical issues into clear options and decisions.
• A collaborative, pragmatic approach, with the ability to mentor others without losing sight of hands‑on delivery.
• Familiarity with related standards and guidance such as DO‑330, DO‑331, DO‑332, DO‑333, ARP4754A/B, DO‑278, DEF STAN 00‑55 or DEF STAN 00‑56 would be beneficial.

Responsibilities

• Design, develop, test and maintain embedded software for airborne systems, primarily using C, with C++ and Python where appropriate.
• Contribute across requirements, architecture, detailed design, implementation, integration, verification and certification support.
• Work closely with systems, hardware, test and flight operations teams to diagnose issues, make sound technical decisions and deliver aircraft‑level outcomes.
• Lead and contribute to software architecture discussions, technical reviews, code reviews and engineering best practice.
• Support software integration, debugging, test automation and continuous improvement of development processes.
• Provide technical guidance and mentoring to other engineers, helping the team build capability and confidence.
• Assess new tools, methods and technologies where they can improve quality, reliability or productivity.

Skills

C programming

C++

Python

Embedded software

DO-178C lifecycle

Safety-critical

Mentoring

Airborne software

Job description

Hours: 37 – Hybrid AALTO, a global leader in Stratospace. Based in Farnborough, AALTO is an Airbus subsidiary that manufactures, operates, and delivers services with its solar-powered, stratospheric platform: Zephyr.

Location: Farnborough Contract Type: Full Time, Permanent Hours: 37 – Hybrid AALTO, a global leader in Stratospace. Based in Farnborough, AALTO is an Airbus subsidiary that manufactures, operates, and delivers services with its solar-powered, stratospheric platform: Zephyr.
Zephyr’s persistence enables continuous flight for months at a time. Its current flight-time record of over 67 days in the stratosphere. From above 60,000+ft, or 20km above ground, AALTO can deliver several applications including direct-to-device connectivity and high-resolution Earth observation.
AALTO operates in a new operational layer between most of air traffic and low-Earth orbit, Stratospace. This is where high-altitude platforms led by Zephyr deliver services to commercial and government partners. We can help monitor environments, observe borders, track natural disasters and connect unconnected communities.
Join us as we create a new domain of aerospace: Stratospace. You’ll be part of a highly-skilled, innovative and passionate group of people – Team AALTO. Together, we can Unlock Stratospace.

About The Role

We’re looking for an experienced, hands-on Principal Software Engineer to take a senior technical role within a multidisciplinary team developing safety‑critical aircraft software. This is an opportunity to work close to the product, influence engineering decisions and help shape robust airborne software that will operate in demanding real‑world environments.

You’ll design, develop, verify and maintain embedded software primarily in C, with C++ and Python also part of the engineering toolkit. Working across the full software lifecycle, you’ll collaborate with systems, hardware, test, certification and flight operations colleagues to solve aircraft‑level problems and deliver high‑integrity software in line with rigorous safety and quality expectations.

This is a senior individual contributor role, suited to someone who enjoys deep technical work, clear engineering judgement and supporting others to raise the standard of delivery. You won’t need to be an expert in every technology from day one, but you will bring strong software engineering fundamentals, curiosity and the confidence to learn quickly in a complex domain.

Responsibilities To Include

• Design, develop, test and maintain embedded software for airborne systems, primarily using C, with C++ and Python where appropriate.
• Contribute across requirements, architecture, detailed design, implementation, integration, verification and certification support.
• Work closely with systems, hardware, test and flight operations teams to diagnose issues, make sound technical decisions and deliver aircraft‑level outcomes.
• Lead and contribute to software architecture discussions, technical reviews, code reviews and engineering best practice.
• Support software integration, debugging, test automation and continuous improvement of development processes.
• Provide technical guidance and mentoring to other engineers, helping the team build capability and confidence.
• Assess new tools, methods and technologies where they can improve quality, reliability or productivity.

Skills And Knowledge Required

• Significant hands‑on software engineering experience, ideally around 10 years or more, with a strong background in embedded or real‑time systems.
• Experience taking airborne software through the full DO-178C lifecycle and supporting aircraft certification activities.
• Strong C programming skills, with practical experience in C++ and Python.
• Sound understanding of software architecture, design trade‑offs, debugging and verification in safety‑critical or highly regulated environments.
• Experience working with multidisciplinary engineering teams and translating complex technical issues into clear options and decisions.
• A collaborative, pragmatic approach, with the ability to mentor others without losing sight of hands‑on delivery.
• Familiarity with related standards and guidance such as DO-330, DO-331, DO-332, DO-333, ARP4754A/B, DO-278, DEF STAN 00-55 or DEF STAN 00-56 would be beneficial.

Why this role?

You’ll join a team tackling technically challenging problems where software quality, engineering discipline and real‑world impact matter. If you enjoy working close to complex systems, influencing technical direction and building software that has to perform when it counts, this role offers the chance to do meaningful engineering at principal level.

In Addition To An Attractive Market‑aligned Salary, We Offer

• Rewarding Excellence: Benefit from our short‑term incentive plan that rewards your hard work and dedication.
• Enjoy Your Time Off: Benefit from 25 days of holiday to relax and recharge.
• Stay Healthy: We’ve got your health covered with private medical insurance, along with dental and optical cash back.
• Secure Your Future: Take advantage of our personal pension plan to ensure a comfortable retirement.
• Peace of Mind: Our income protection and life assurance schemes are there to support you when you need it most.
• Getting around: Drive the latest vehicles with our discounted salary sacrifice scheme.
• We Care About You: Our employee assistance programme is always available to provide the support you need.
• Perks Galore: Enjoy a range of employee discounts via Perkbox, from household goods to travel!

At AALTO, we take pride in building and offering an exceptional work environment that values your well‑being and rewards your dedication. We believe in recognising your hard work and commitment, which is why we provide a fantastic bonus scheme that rewards your contributions. Additionally, we understand the importance of financial security and support your future with a competitive pension plan. When you join us, you become part of a workplace that not only encourages your professional growth but also cares about your personal fulfilment and financial stability.

AALTO is an equal opportunities employer and positively encourages applications from suitably qualified and eligible candidates regardless of sex, race, disability, age, sexual orientation, gender re‑assignment, religion or belief, marital status or pregnancy and maternity.