Case study
February 5, 2024
By joining forces, Mainblades and KLM Engineering & Maintenance (E&M) are showing the aircraft maintenance industry that drones are ready to be used in operational environments for visual inspections.
The result of the cooperation is that inspection times have been reduced by 75% while providing five-times more accuracy compared to the traditional, manual inspection method.
We can now monitor the paint peeling progression, predict future repairs, and allow for informed decision making.
The Boeing 787 Dreamliner family and the Airbus A350 both consist primarily of composite materials. Whilst this material is known for its exceptional lightweight performance, it is also prone to paint peeling.
KLM E&M follow Boeing’s recommendation to conduct regular visual checks: to visually document the progression of the damages, and to apply temporary high-speed tape on areas already affected. Currently these are done manually.
This is time consuming
Causing the Dreamliner to stay on the ground for longer than necessary.
This gives us inconsistent inspection data
As inspections are carried out manually, inspection photos are inconsistent in angles, distance to the aircraft, and levels of exposure. This makes it a challenge to understand the progression of damage over time.
With over 100 of these visual wing paint inspections per year, KLM and Mainblades jointly identified the need for an automated, streamlined and standardised approach.
As this task is not included in either the Maintenance Planning Document (MPD) or Aircraft Maintenance Manual (AMM), but rather in the Service Letter, it meant that there were no specific guidelines on how to document specific inspection results. As this inspection was originally set up by KLM, the way of collecting the data could be done both manually and automatically. This proved a great opportunity to translate this particular traditional task card into a digital one.
We took KLM’s traditional inspection task card and translated it to a drone inspection path, which functions as a digital task card.
The traditional task card tells a mechanic to:
The digital task card tells a mechanic to:
KLM gave us access to their aircraft, enabling us to optimise our image capturing process. We started with experiments, to ultimately get the drone to fly a consistent path around the Boeing 787 aircraft. It had to maintain the same speed, as well as keep a consistent distance to the aircraft to ensure high-quality image capture.
This was achieved using Mainblades’ path planning feature (figure 3). This path planner uses a 3D models of the aircraft to plan the flight path on.
Through the initial trials it was discovered that the drone required 15 minutes to capture high-resolution images of both wings, immediately demonstrating the opportunity for drastically reduced inspection time.
With these initial, promising results, the project then moved into the validation phase. KLM E&M and Mainblades worked together to conduct a series of human vs. drone trials to compare and validate the speed and accuracy of drones compared to manual inspections.
The manual inspection
60 mins: Mechanic takes photos of the aircraft wings from a cherry-picker.
120 mins: The engineering department generates a report: An excel sheet is filled in to estimate (inaccurately) the size and location of paint issues from the photos the mechanics took.
Estimated tape size: 0.35m2
The automated drone inspection
5 mins: Setting up the drone
15 mins: Inspection of both wings: 50 high-quality photos are taken.
15 mins: Our software generates a report: The photos are analysed for findings. Our user friendly software enables to intuitively review findings. Additionally, we leverage AI to make the process even faster. The report gives a schematic overview of the exact size & location of paint issues (figure 5).
Estimated tape size: 1.7m2
Results:
75% faster
5x more accurate (actual tape size was 1,88m2)
What we did next
Based on KLM’s regular feedback from all layers of the organisation we then developed a web portal in which KLM mechanics can:
use to review inspection results
share findings with stakeholders
generate reports
… and ultimately: make informed decisions.
After validating the inspections results and developing the web portal, we implemented the new inspection method into daily operations.
Approval
KLM did not need to obtain approval at all; they need to follow the MOE guidelines, setup by their Quality Assurance and enforced by the Civil Aviation Authority.
KLM E&M can specify this as an ‘Alternative Means of Compliance’. They do this by following both the steps in the checklist of the MOE guidelines, and by performing the validation tests as determined by Engineering.
Since paint peeling & high-speed tape inspections is not linked with requirements specified in the MPD, no consultation or approval from the aviation authority was necessary in this case. Additionally, since the new method is not considered an AMM inspection either, consultation with the original equipment manufacturer (OEM) was also not required.
Meanwhile, automated paint peeling and high-speed tape inspections have reached full operational status at KLM E&M.
What’s next
The project partners are already looking at other possible inspections, such as Lightning Strike, Placards, and broader GVI-equivalency. Succesful preliminary tests for these new use cases have already taken place and will continue in the near future.
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