With growing pressure from a variety of drivers on MRO staff resources and expertise, and in the context of growing digitalisation of MRO processes, drone-based hangar inspections are arriving into workshops as a technological solution to a tricky problem. To learn more about how drone inspections work, how the technology is developing and what the key applications are, we sat down with Michael Sprehe, chief brand architect at specialists Mainblades, who work with KLM Engineering & Maintenance, Lufthansa Technik Philippines, and Delta TechOps.
Adding accuracy, data consistency and speed to the process of inspecting aircraft, Sprehe says, “drones fit right into the megatrend of digitalisation and automation. Every MRO is looking to optimise their processes through all kinds of technologies, so drones fit right into that.”
The essential hardware package is a customised, sensor-equipped professional drone, a cellular connection to a ground control station with an iPad, and a technician to monitor in case of any abnormalities. When activated, the drone is programmed to fly around an aircraft within the hangar environment, using its sensors to replicate fingertip and visual inspection with all the complicated access requirements that entails. It then returns to its ground control station and transmits its images and data, which then are uploaded for cloud storage and processing with AI and machine learning.
Benefits accrue, Sprehe says, “in terms of efficiency gains, in terms of making data and analytics based decisions, in terms of safety, in terms of getting insights also from remote locations — not just the inspector performing inspection in the hangar but also maybe his managers, decision makers might be in a completely different location having access.”
This remote access benefit was clearly demonstrated during the lockdown phase of the COVID-19 pandemic, where expert technicians were often prevented from travelling to MRO locations, and hangar environments posed close-working risks — very much a pandemic innovation that is now bearing fruit post-lockdown.
“In the last couple of years, we really laid the foundation for technology to work, really focusing on the enabling technologies: that means autonomous flight, so making sure that the drone can fully autonomously fly in an operational aircraft environment, and the related foundation for machine learning algorithms, to identify damages,” Sprehe says. “In the last one to two years, we moved to a new phase, which is basically the operationalisation: the rollout of technology, putting it into real life, hangar environments, and flying inspections with partners. Even though the technology is not fully certified, yet, it is important that we put it into the hands of the aircraft engineers to get experience with it.”
At present, Mainblades uses the robust, professional-grade DJI drone platform that will be familiar at least in passing, but is moving towards a drone-agnostic model, enabling any kind of drone — depending on the MRO partner’s preferences — to be used for these purposes. On the platform is mounted a high-resolution camera and LIDAR (light detection and ranging) device, with the company planning a depth measurement sensor for 2024.
“It’s a question we receive a lot,” Sprehe says: “can you measure the depth of a dent? That is just the beauty of such a modular flexible system: we can just very flexibly add any kind of new sensor to it, depending on the need and the use case.”
The drone also contains a 3D model of the airplane, which helps both in the scanning for abnormalities and to ensure obstacle avoidance in the busy and often conflicted hangar environment, with its moving stairs, expensive equipment and, of course, people.
“On the software side, we have everything that’s related to autonomous flight, to machine learning, recognising damages, to the whole application on the iPad, to stay in control during the inspection, as well as an online portal, that you can also access data from remotely. You can see all the photos and the damages and the inspection reports,” Sprehe explains, noting that the imagery is then transmitted into the cloud for “image processing through our machine learning stacks. We trained our datasets, using expertise from the aircraft mechanics themselves. They helped us in labelling tons and tons of photos, making sure that the algorithms actually work properly. Our software interfaces really also evolved from just pure functional stacks to really nicely designed software interfaces that are easy and intuitive to use for mechanics, to run an inspection as easily as possible.”
The whole process from drone to portal will take just a couple of minutes over the cellular connection, after which the AI and machine learning work is kicked off.
In terms of incorporating drone inspection into the wider MRO industry, Sprehe says, “in terms of the challenges, I think it’s mainly two things. It’s a change of mindset, first of all: it’s a completely new way of working. So management of change is important. Our philosophy is that we put a big focus, not just on the product itself, but also really on the fit with existing workflows, that we tightly collaborate with the partners to make sure we understand exactly how they work and build the software in such a way that it matches with the way they already work. That’s an important one. The second main hurdle or challenge is, of course, the regulatory and certification side of things, although we’re making really good progress on that as well.”
Indeed, Mainblades recently received Part 145 certification for paint peeling and high speed tape inspections on the composite wings of Boeing’s 787 Dreamliners. Paint peeling on carbon fibre reinforced polymer and other composite skin materials has been a major topic of discussion within the industry recently, and detecting it for remedial work is crucial.
“It’s a very particular use case,” Sprehe explains. “Essentially, the A350s and the 787s of this world are made, in a big part, of composite materials, and KLM Engineering & Maintenance approached us. So we developed it, rolled it out, trained mechanics from KLMEM, and rounded off the Part 145 certification for it.”
Author: John Walton
Published 05 December 2023
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