During a recent tour TWZ took of the RTX-owned Pratt & Whitney’s jet engine assembly plant in Middletown, Connecticut, nearly everything was quiet on the line following a major push to complete outstanding deliveries by the end of the second quarter on July 1. But the Bearing Automation Robotic Builder – known familiarly as BARB – remained calmly at work, completing assembly processes for the #2, #5, and #6 bearings on the company’s commercial 1100G – one of the company’s GTFs, or geared turbofan engines, powering several Airbus and Embraer fleets.
While robotic assembly machines are a commonplace sight on factory floors building everything from cars to electronics, Pratt & Whitney’s assembly lines are still largely human-dependent. That’s a function, in part, of the exacting and unforgiving work of building jet engines, which require a carefully policed logbook of production steps executed to keep the process error-free. Throughout the factory floor, “Foreign Object Debris” bins remind workers to keep areas clear of any loose materials, from stray threads to gum wrappers. Even small pieces of detritus can become deadly if they end up in a jet intake. Company staff stressed that ensuring a machine could operate error-free in a range of conditions was a time-consuming and critical prerequisite for embracing automation.
BARB, which fits the mold of a factory robot out of central casting with its upright stance and long yellow arms, is the product of a $20 million investment the company has made into automation. It’s a modest first step at integrating automation more fully throughout jet engine assembly – both on the civilian side and in the somewhat more complex military engine business on a parallel production line in the same facility.
According to Ted Sluis, vice president and manager of Product Delivery Centers at Pratt & Whitney, BARB arrived in Middletown around late 2024, but only came online this spring after extensive testing that ensured the robot’s cameras and sensors could reliably identify parts and consistently perform the correct operations.
“There is a visual inspection aspect of it, and when we were doing the initial trials of the parts, we were using scrap parts,” Sluis said. “But the scrap parts were old, and we went to make production parts on it, those were new and shiny. The vision system started having issues because it wasn’t used to shiny parts; it was used to like the old parts … little things like that, that we had not anticipated. And so a lot of learning meant that it took us all the way through last year, into the beginning of this year to get it to where it could repeatedly get through the entire cycle without a person intervening to do something.”
According to public production and training manuals, the 1100 engine, which is assembled in a horizontal position, has seven total bearings requiring assembly. The #2 bearing is a ball bearing that supports the front of the low-pressure (LP) rotor, which extracts energy to power the engine fan and reaches maximum speeds above 10,000 RPM. The #5 and #6 bearings are rear roller bearings.
Sluis said engine assembly involves bearing sub-assembly, including the bearing, housing components, and affiliated seals and covers.
“So it’s a handful of parts that you have to get put together into a sub-assembly,” he said. “With the types of operations that we’re doing, different parts have different clearances. And so to get them to go together, you have to heat one part and cool another part, and you have to orient those in the right way, press them together, let it normalize, inspect it to make sure that it actually meets the right dimensional requirements.”
In the traditional engine assembly process, he said, a mechanic would sign a record at every stage verifying the prescribed action had been completed in the correct order. Integrating the assembly robot into the record-keeping process has been another deliberate effort, Sluis said.
“If a person is doing that work, they would be signing with their badge all the different sequences to say ‘I completed this work..’ In this case, the mechanic is basically signing, saying, ‘I provided the parts to the machine, the machine is tracking, I did this, I did this, I did this,’ and that’s going to be part of the engine build record. The mechanic signs, saying, ‘I received the assembly from the automation machine, and I’m going back to the normal process.’”
While the approach to integrating automation into an exacting assembly process has been small-scale to start, Sluis said the benefits in efficiency have been immediately clear, with an 80% reduction in ‘touch time.’ When reporters visited the production line July 1, the robot appeared still, but it was in reality actively supervising the heating of parts in an oven while standing by to complete the next assembly steps. But the biggest benefit to bringing BARB online, Sluis said, has been the proven error-free repeatability.
“If you look at the yield of that sub-assembly, it’s essentially 100%,” he said. “I think that, of all the ones that we’ve made since we went into serial production with it, we had one that had an issue and it was something that had to do with the part going in, as opposed to what the machine was doing with the parts.”
That deliberate work has taken place in parallel with Pratt & Whitney’s efforts to integrate AI into engine production. It recently debuted an AI-assisted borescope inspection software for its powerful commercial V2500 engine and has already completed pilot test cycles on both the GTF commercial engines and the F135 engine, which powers all variants of the F-35 Joint Strike Fighter.
The AI support tool purports to help human inspectors by applying trained analysis to video of the borescopes to identify any variations more quickly and consistently.
“Broadening the integration of AI-assisted inspection capability strengthens our ability to detect issues earlier, improve turnaround times, increase time on wing and reduce operational disruption for our customers,” Rob Griffiths, senior vice president of Commercial Engines Operations, said in a released statement. “It will fundamentally reshape how engines and components are inspected, maintained and supported throughout their lifecycle, as we increase its application across Pratt & Whitney.”
The notion behind both technology applications is that a meticulously trained robot will beat even a seasoned human inspector for accuracy and consistency.
“I think our biggest benefit will actually be in the quality signature,” Sluis said.
The multi-year plan for automation will gradually branch out to more complex automation applications, Sluis said, moving next to “small modules that do not have rotating parts” before moving to those that do have moving components.
The next spot for an automation machine has already been chosen: it will be the 1100G’s central diffuser module that has fuel nozzles mounted to it and is positioned in front of the high-pressure turbine. Pratt & Whitney is currently building a 2,600-square-foot site where the robotic assembly can take place, Sluis said, with a robot six times as large as the roughly human-sized BARB. The company expects it to be up and running on the line a lot sooner after delivery than its first robot.
“Our lead time from when it arrives to when we’re making modules off of it should be much, much shorter than we experienced with BARB,” Sluis said.
Military customers, company execs said, have already expressed “tremendous interest” in building automation into their engine assembly plans. Sluis and Chris Olivo, the Middletown product delivery center customer and event manager who led the production line tour, said the long-term goal saw every line benefiting from BARB-like robots.
One hurdle is the way the engines are assembled. While the 1100G and F139 engines, the latter used for the Air Force’s KC-46 Pegasus, both tip horizontally for assembly, the F135 is assembled vertically in pits on the floor. This makes it more difficult for a non-human operator to isolate and access some assembly processes.
Then, Sluis said, the higher dexterity needed for a lot of engine assembly processes required additional testing and development. He cited, in particular, fixing nuts and bolts onto assemblies as processes conducive to human dexterity. Once those issues are solved, dissemination of jet-assembly automation technology could move quickly.
“From there, it all depends on volume, business case or interest,” Sluis said. “But at least the capability will be foundationally established.”
Contact the editor: Tyler@twz.com