ATA Chapter 29 hydraulic systems are widely used in commercial aircraft to operate landing gear, wheels, brakes, flight controls, thrust reversers and other flight- and safety-critical components. Their reliability is thus critical to efficient flying, and doing predictive maintenance before defects ground aircraft can be a huge gain.
Fortunately, hydraulic systems seem to be amenable to the kind of monitoring and algorithm development that predictive maintenance relies on. Josh Melin, product line director at Honeywell Forge Connected Maintenance, says any aircraft that captures sufficient and sufficiently frequent parametric data on the health of its hydraulic systems is a good candidate for predictive maintenance on hydraulic systems. This requirement is certainly met by the latest generation of aircraft, such as the Airbus A350.
Forge uses both aircraft condition monitoring system and quick access recorder data to develop its predictive models for hydraulics. Also helpful are technician logs that record symptoms, failures, troubleshooting actions and replaced parts.
Melin says Forge’s predictive tools for hydraulics are able to reduce 80% of delay events and 40% of minimum equipment list events. “That means our solution can catch on average 80% of the imminent failures on the hydraulic LRUs that we cover before they become failures that impact the operation that would cause operational interruptions. And our solution can catch on average 40% of the imminent failures on the hydraulics LRUs that we cover before they would become an MEL (minimum equipment list) event.” He says false warnings are relatively rare. “The accuracy of our hydraulics predictive models is over 95%.”
Still, this is a relatively young field for Forge’s predictive tools. Melin says that only 36 aircraft so far are using Forge predictive maintenance for hydraulics.