Product & Reliability Mechanical Engineer

About HyLight
HyLight's mission is to help society become more resilient to climate change by improving the observation and inspection of infrastructure.

We build HyLighters, airships that collect data across vast distances with zero emissions.

Our Activities Include

• Detecting methane leaks from gas infrastructures (4% of global GHG emissions)
• Inspecting power lines to prevent outages and wildfires

By 2030, we aim to become the global leader in aerial monitoring.

In just 3 years, we have pushed the realm of possibilities: as we have:

• Developed 8 iterations of the HyLighter
• Logged over 300 flight hours
• Secured our first inspection contracts with Europe's largest infrastructure operators
• Joined the world's top startup accelerator, Y Combinator
• Raised €6 millions

HyLight is aiming for a diverse and included team, if your profile doesn't fit all the description but you can bring a diverse point of view, push it forward, it will be highly appreciated.

We're well-funded and backed by top investors, providing the resources you wish you had when building your own business. We don't care about traditional roles or titles—just that you're smart, proactive, and bring the same founder-level ownership and drive to help us build something massive.

At HyLight, our mechanical philosophy is simple yet demanding:
Building the Future, Securing the Present.
Personal Note from Louis (Airship Mechanical Design Team Lead)
"We are tackling a massive challenge: making innovative airships fly while guaranteeing flawless operational availability. To achieve this, we refuse to work in silos. We are one polyvalent force driven by a
'Dual-Track Agile'
mindset.
This role requires a rare balance. You won't just be a designer behind a screen; you will be an owner.

• In 'Discovery' Mode, you will explore and design the future HyLighter versions. You'll have the autonomy to iterate, fail, and find the best solution to complex physical problems.
• In 'Delivery' Mode, you shift gears to efficiency and rigor. Here, we don't look for perfection; we look for reliability and speed. You'll get your hands dirty in the workshop, ensuring that what we validate today flies tomorrow.

I am looking for someone who thrives in this duality. Someone who treats the shop floor with as much respect as the design studio, and who understands that a design isn't finished until it works in the field. If you are ready to take full ownership of the mechanical lifecycle and build something that truly matters, welcome to the team."
Job Summary
As a
Mechanical Design & Reliability Engineer
, you will be the technical owner of the drone's mechanical lifecycle. You will bridge the gap between "engineering perfection" and operational reality, ensuring our drones are robust, easy to assemble, and available for mission-critical inspections

The Mission
In collaboration with the Mech Team, your responsibilities will focus on Reliability, Industrialization, and Continuous Improvement:

• Creative Design: Lead the conceptual design of new mechanical subsystems and airframe evolutions. You will transform innovative ideas/prototypes into functional products through rapid iteration (CAD, 3D printing, machining), balancing sleek aesthetics, design for manufacturing with high-performance engineering.
• Reliability & Lifecycle Management: Establish fatigue models and design accelerated life tests (HALT/HASS) to predict component "End of Life" and maximize fleet availability. You will robustify the drone design to ensure reliable operation in challenging conditions.
• Root Cause Excellence: Implement a systematic Root Cause Analysis process for every field failure, ensuring rapid design updates and maintaining a strong feedback loop between engineering and operations.

Profile Sought

• Background: Mechanical Engineering degree or equivalent practical experience.
• 3+ years experience in designing resistant outdoor/rugged mechanical systems (material fatigue, vibration).
• Versatility: You accept dual roles, comfortable alternating between deep design work (New Versions) and operational urgency (Production Support).
• Mindset: You possess a "Shop Floor" mindset, you enjoy spending time in workshops and do not consider work finished until the physical product is validated, not just the CAD file sent.

Technical Skills

• Core Mechanics: solid CAD & DFM expertise (Design for Assembly, reduced part count), Material Mechanics (S-N curves/Wöhler, UV aging, creep, stress cycles).
• Reliability Data: Comfortable with statistical methods for reliability and data-driven approaches (Python).
• Manufacturing: Comfortable with processes such as 3D printing, welding, machining, or sheet metal work.
• Analysis Methods: Mastery of problem-solving methods like 5 Whys, Ishikawa to trace field failures to root causes.

Soft Skills

• Highly organized and detail-oriented in documentation and execution
• Entrepreneurship: Willingness to find shortcuts and ways to do things efficiently.
• You enjoy getting your hands dirty and respect the insights of the technical team.
• Willingness to be present on-site and support operational teams during test and flight activities
• Curious, analytical, eager to learn, and proactive in problem-solving
• Good communication skills and collaborative mindset

Languages

• French AND English: Fluent (Required)

What We Offer

• Annual compensation: €45,000 - €60,000 (based on experience)
• 100% reimbursement of public transport pass (Navigo) or €800/year for sustainable commuting
• Bike provided for commuting
• Free lunch
• Bi-annual offsite trips with the whole team
• Excellent work environment: international team, team events, beautiful offices on a former airbase

Why You Should Join

• Founder Mentality: We value extreme ownership and want people who think like founders-fast decision makers, natural problem solvers, and executers.
• Ground Floor Opportunity: You'll be helping to shape and grow a revolutionary company with the resources to back it.
• Impact & Speed: Work in a fast-paced environment where your contributions will have immediate, tangible effects on the company's success.

Interview Process

• Introductory phone call (20 min)
• Video interview with our Airship Mechanical Design Team Lead Louis (40 min)
• A 2 hour technical case study followed by a debrief with team members
• Reference calls
• On-site meeting with the team and founders (1h)

Location:

• Office : Base 217, Brétigny-sur-Orge, accessible via RER C.
• Lab and Warehouse access
• You'll work side-by-side with experts in embedded, aerospace, and hydrogen propulsion systems—where your impact matters from day one.