Mechanical Engineering Internship

About HyLight

Power lines, gas pipelines and railways are still inspected the way they were 50 years ago: by helicopter. Expensive, noisy, and up to a tonne of CO₂ per flight hour.

We built the alternative. The HyLighter is a 12-metre autonomous airship running on hydrogen. It flies for up to 10 hours, almost silently, and spots a 1 mm defect from 25 metres up.

But the airship is only half the story. Every flight brings back massive amounts of LiDAR, imagery and methane data, and that’s where the value is. Our AI turns it into what operators act on: 50+ types of defects detected automatically, and leaks pinpointed across their network.

It’s not a prototype. HyLighters already fly missions for France’s largest energy and rail operators and have flown over the Palace of Versailles. Backed by Y Combinator, we just raised €13M to go from 4 airships to 15.

Working at HyLight

We design, build and fly every HyLighter, and turn its data into insight, all under one roof on a former airbase. Which means:

• You own it all the way. At a big aerospace company, you’d own a small piece of one subsystem. Here, you design it, test it, stand on the airfield when it flies, and see the client act on the data it brings back.

• Weeks, not years. Ideas go from whiteboard to flight test in weeks.

• Responsibility from day one. The founders’ average age is 27. Nobody here waits for permission.

We don’t care about titles or ticking every box. We care about what you build and the perspective you bring, so if your profile is different, apply anyway.

Personal Note from Louis (Airship Engineering 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 Integration and Test Intern, you will contribute to the mechanical lifecycle of the HyLighter. You will bridge the gap between engineering design and operational reality, helping ensure our airships are robust, easy to assemble, and reliable for mission-critical inspections.

The Mission:

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

Creative Design: Contribute to the conceptual design of new mechanical subsystems and airframe evolutions. You will help transform innovative ideas and prototypes into functional products through rapid iteration (CAD, 3D printing, machining), balancing sleek aesthetics, design for manufacturing, and high-performance engineering.

Reliability & Lifecycle Management: Support the development of fatigue models and design accelerated life tests (HALT/HASS) to predict component "End of Life" and maximize fleet availability. You will contribute to improving the drone design to ensure reliable operation in challenging conditions.

Root Cause Excellence: Support the implementation of Root Cause Analysis processes for field failures, helping ensure rapid design updates and maintaining a strong feedback loop between engineering and operations.

Profile Sought:

Education: Final-year Master's degree (or equivalent) in Mechanical Engineering, Aerospace Engineering, Materials Engineering, Product Design Engineering, or a related field.

Experience: Previous internship(s), academic projects, research experience, or hands-on work involving mechanical design, prototyping, testing, manufacturing, or mechanical integration.

Background: You have worked on mechanical systems, aerospace structures, robotics, drones, automotive, or other complex physical systems through internships, university projects, student teams, or personal initiatives.

Versatility: You enjoy alternating between design and hands-on work, contributing both to the development of new concepts and to the improvement of existing systems through testing and iteration.

Mindset: You possess a "Shop Floor" mindset. You enjoy spending time in workshops, building prototypes, testing solutions, and understanding that a design is only complete once the physical product has been validated.

The following list of skills is exhaustive, while you may not perfectly fit with the profile, we highly value personal growth and development. We see our interns as potential future technical leaders at HyLight.

Technical Skills:

This is an exhaustive list of sought-after skills. While you may not have experience in all of them, we are looking for strong fundamentals, curiosity, and a willingness to learn.

Core Mechanics: Knowledge of CAD design and mechanical engineering fundamentals, with exposure to Design for Manufacturing (DFM), Design for Assembly (DFA), material mechanics, and mechanical validation.

Reliability Data: Understanding of mechanical testing principles, fatigue, vibration, stress analysis, and reliability concepts through coursework, projects, or internships.

Manufacturing: Hands-on experience with processes such as 3D printing, machining, welding, or sheet metal work is a strong advantage.

Analysis Methods: Familiarity with problem-solving methodologies such as 5 Whys, Ishikawa diagrams, and structured root cause analysis.

Data Analysis: Ability to analyze test results and extract insights using tools such as Python is a plus.

Soft Skills:

• Highly organized and detail-oriented in documentation and execution.

• Entrepreneurship: Willingness to find shortcuts and ways to do things efficiently while taking ownership of projects.

• 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:

English: Fluent (Required)

What We Offer:

• 2000 to 2500€/month compensation

• Real responsibility and direct impact on cutting-edge autonomous flight technology

• Mentorship with the Tech and Engineering teams

• Become a shareholder in HyLight upon hiring

• 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)

• A 2 hour technical case study followed by a debrief with team members

• On-site meeting with the team and founders (1h)

• Reference calls

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.