Helikopter - Airbus og H225 MGB monitoring - AW&ST

Airbus Big Data Project Could Bring Earlier Warnings Of Gearbox Faults Tony Osborne  Airbus is exploring the potential of widening the scope and capability of its future Health and Usage Monitoring Systems (HUMS) to provide earlier detection of potential problems with the moving components inside helicopter transmissions. The research—an in-house project—is an offshoot of the company’s engineering work following the fatal crash of one of its H225 helicopters in Norway in April 2016. In simple terms, helicopters’ HUMS use a series of accelerometers placed at critical points in the aircraft’s dynamic system such as the main and tail rotor gearboxes to monitor vibration levels. Variations detected can provide imperative early warning of a potential issue. In the Norway accident, Airbus and Norwegian investigators believe the accident likely was caused by spalling within the outer ring of one of eight planet gears within the main gearbox. This resulted in a crack that propagated, causing it to split in two between two teeth and collide with a tooth on the sun gear. Airbus using new generation sensors to spot degradation in moving elements of a helicopter transmission Company plans to install sensor kit on 10 H225s to understand the “healthy” operating regime Within moments, the inertia of the helicopter’s main rotor sheared off the top section of the main gearbox, which resulted in the main rotor head and blades separating from the aircraft. But trying to detect a potential problem in this section of the gearbox—where the planet gears are operating and dozens of parts are intermeshing simultaneously and at different speeds depending on the mission and environment in which they are operating—is a significant challenge. “It is like attempting to find an irregularity in the heart of child while they sit in a classroom with other children, using sensors placed out on the outside of the building,” says Regis Magnac, Airbus head of customer relations. “There are hundreds of points of connection that are turning very fast at different rhythms. . . . It is very noisy and there are so many frequencies,” he says. But data collected during test bench trials and flight tests suggest new-generation sensors combined with advanced algorithms and data processing could provide extremely early warning of component degradation. As part of the engineering work, Airbus has been assessing H225 gearboxes on a static test bench. The gearboxes hold additional sensing equipment. Artificial degradation was added to components to see how it would evolve. The new sensors, capable of seeing higher bandwidths of frequencies than previous generations, have been providing a lot of new data, says Magnac. This data was then worked through different algorithms, and an “evolution of the propagation,” has been tracked through those algorithms. “I am not saying we have found the gold solution, but we’ve seen some interesting developments; interesting enough for us to continue to deep dive into it,” says Magnac. “It’s not for the near future, that’s for sure.” The trials may be at an early stage, but Airbus is working with several customers on the installation of monitoring equipment, separate from the HUMS. Ten H225s will be outfitted to supply operational data in the coming months. “If you want to understand and detect an irregularity in a heartbeat, you obviously need to know what a healthy heart is doing,” says Magnac. “We need to go through that in order to make sure our understanding of what is good is right in order to better tune our algorithms to what we want to look at,” he adds.

Airbus is working with H225 operators to install a sensor to better understand a “healthy heartbeat” within the main gearbox. Credit: Airbus Helicopters

By using customer aircraft, Magnac says Airbus will able to build data from aircraft operating in different environments as well as gather it far more quickly than it would simply by using its own test aircraft. The company is preparing a data center to collect the information from the aircraft to feed the research program. A key part of the work has been studying the best positioning of the additional sensors around the transmission. “Where a doctor places his stethoscope, you will hear different things . . . so the algorithms need to be tuned for a certain position,” says Magnac. Rotary-wing aviation may be evolving toward multirotor systems, but while the traditional helicopter remains in operation, the main gearbox will always be what Magnac describes as a potential “single point of failure,” which cannot be resolved through redundancy like other aircraft systems. Additional monitoring can provide additional reassurance, he says. The H225 is the focus of the company’s research now, but success could lead to the technology eventually having implications beyond helicopters. “Cyclic gear trains are used in many industries, not just helicopters, but also in cars and wind turbines,” -Magnac says, adding, “There is criticality in anticipating what happens in those [wind turbines], but such a system does not exist.”