Delivering the Airbus A350-900 flap actuation system with zero margin for error
In aerospace manufacturing, there are situations where there is no room for iteration, no margin for error, and no second chance. This was exactly the context in which BMT Aerospace Belgium took on one of its most demanding technical projects of the past decade. The Airbus A350-900 flap actuation system.
From slat actuation to flap systems
Today, every Airbus aircraft flies with BMT-produced racks and pinions that actuate the front wing slat, the movable leading-edge surface of the wing. This long-standing position reflects years of experience in flight-critical gear systems and a proven quality track record.
BMT Aerospace Belgium was asked to extend its scope to the rear wing flap system for the Airbus A350-900.
Unlike the slat system, the flap mechanism is not gear-based. The LBA (Lever Bearing Actuator) is a rod mechanism assembly consisting of approximately 25 individual components, including a critical arm featuring a high-precision spline. The accurate manufacturing and integration of this spline is a key area where BMT’s expertise makes a decisive difference.
Taking over a critical assembly under pressure
The flap assembly for the A350-900 had historically been produced at locations outside Europe. Due to persistent quality issues in the existing supply chain, the customer, which delivers the assembly to Airbus, asked BMT Aerospace Belgium to take over production.
This decision was based on two factors. First, BMT’s strong quality reputation with Airbus. Second, nearly ten years of experience producing a similar LBA system for the A350-1000.
The urgency of the situation was exceptional. In November, Airbus directly contacted BMT to request immediate delivery of parts in order to avoid a potential line stop.
No prototype. No learning curve. No margin for error
The project came with a set of challenges rarely combined in a single industrialisation effort.
There was no prototype phase. Production started immediately at series level, with first batches of up to 15 assemblies for some variants. From the very first part, first time right was essential.
The design itself dated back more than ten years and had been developed without BMT’s involvement. Industrialisation therefore had to proceed without full insight into the original design rationale behind certain drawing requirements.
In addition, highly specific surface treatments required parts to be sent to the United States and Asia, creating a complex global supply chain. This had to be managed alongside ongoing logistical disruptions caused by international trade tensions, without delaying deliveries.
Throughout the project, machining accuracy remained a critical challenge, as tight tolerances had to be achieved consistently across multiple components within the assembly.
Delivering under pressure
Despite these constraints, BMT Aerospace Belgium successfully stabilised the production flow. In 2025, the team delivered twice the originally requested volume, while eliminating the immediate risk of an Airbus line stop.
Beyond the numbers, the project significantly strengthened BMT’s relationship with Airbus, reinforcing trust in BMT’s ability to deliver complex, flight-critical assemblies under extreme conditions.
A collective achievement
This project can be considered the largest technical challenge for BMT Aerospace Belgium in the past eight years. It required close collaboration across engineering, operations, supply chain and quality teams, as well as the rapid nomination and training of new suppliers while keeping most of the production in-house.
More than a single program, the project represents a strategic step up the value stream and contributes to a more sustainable long-term future for BMT Aerospace.
When first time right is essential, experience, discipline and teamwork make the difference.