"Hey! This is Your Airplane Talking to You!"

Innovative aircraft health monitoring (AHM) systems have taken the aircraft from an inanimate, reactively maintained object to become a fully-fledged flying CPU delivering detailed data to drive predictive, customized maintenance.


Most operators have installed WiFi at their gates to enable quick downloads of data, for regular diagnostic trend monitoring, when the aircraft is at an airport. However, there’s also the possibility to troubleshoot the data while the aircraft is in flight, for certain fault conditions. Cost and data throughput volume are the main inhibitors to a constant stream of all the data from the aircraft while in flight. And while there is the ability to actually ping the aircraft and ask for specific information during flight, it’s expensive and a data bottleneck. Once a cheaper communication path to the aircraft is established, all of the systems can send data as generated, including having a potential replacement of the flight data recorder.

At Republic Airways Holdings, they’re creating reports to identify and connect events. “We use tools to review aircraft data against pilot/maintenance reports to confirm failure modes and to proactively address issues not presenting themselves directly,” says Stevens. “In many cases, a technician focuses on the fault and not the reason for the fault. We use system-based data to narrow our search of the cause. We ask ourselves ‘what if the valve is doing exactly what it was supposed to do?’ We use this to find the hidden failure before it repeats itself. The direct fault may not be flagging on the airplane, but by sifting through the data, they can establish a possible fault chain. Technicians should not stare at the component that’s failing, they need to find out what is telling the component to fail, and go there.”

While some may see it as looking for the needle in the haystack, the operators and OEMs have come together to sift out the noise and decide what data needs to be acted upon. Some operators have trained their front line and engineering staff to interpret the data. Others have hired specific people experienced in interpreting flight data, who know the aircraft well.

By maximizing and using the right data, the operator can see a significant decrease of their unplanned events. “With a proactive review, we see about a 20 percent reduction in repeat write-ups and ‘soon to fail’ events. We also believe, through a fully implemented AHM program, we can do a lot better,” Stevens adds.

Another benefit to all the data is the operators’ ability to back up their operations performance “stories” for removal reasons. In this case, when a repair station returns a component as “no fault found” or the OEM indicates that the component “can’t do that,” the operator has data to show the repair station the fault as it occurred.

Stevens says it’s been very beneficial to creating a more proactive, collaborative relationship with the OEMs, as well. “Every day I receive emails from vendors and OEMs such as Bombardier, Embraer, Honeywell, and Hamilton Sundstrand asking for the data to be downloaded and sent in for review. These OEM connections create a collaborative effort to rectify the situation or determine the root cause of the event.”

Unfortunately, not all components are yet able to transmit data, but many OEMs are working toward that goal, by requiring certain components to be able to “plug and play” interface with the onboard servers. Some components, however, may never have or need that capability. “There’s always a tradeoff [of cost vs. data need] when looking at what systems have the most impact,” Hapgood points out. “It’s not just carte blanche ‘let’s just increase the data available’,” because the data benefit may not always be there.

Data security

With all the data hacking threats one hears in the news these days, is the aircraft of the future being set up to be another target? “Flight controls and that type of software are completely separated from the performance data,” according to Hapgood. There are also a lot of regulatory and OEM requirements that are put in place and rigorously tested to ensure that hacking of the airplane doesn’t happen. “And from a maintenance point of view, any of the data that comes off the aircraft today and is put into a system, like the Boeing AHM, is closely guarded and not public information.”

Much of the data delivered from these aircraft can be entered into and utilized by operators’ existing maintenance systems. “You do have to think carefully how you design it and who has access,” says Hapgood. It’s not the intent to have multiple systems delivering and storing the data, as this convolutes the message. The systems offered are less complex and are intended to decrease the hands-on requirement to manage and integrate the data.

Revisiting the HAL 9000

“Dave Bowman: Hello, HAL. Do you read me, HAL?

HAL: Affirmative, Dave. I read you.

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