Landing gear needs to be consistently inspected and maintained to ensure the safety of every takeoff and landing. And with consumer demand for air travel rebounding post-pandemic, maintenance providers are working overtime to keep these systems operating at peak performance with minimal downtime for aircraft operators.
So, what are the technologies and trends driving this vitally important market segment, and what do professionals operating both commercial and business jets need to know?
Overhauling Landing Gear
Nextant Aerospace offers a full line of services, including landing gear, brake and wheel overhaul for many types of aircraft.
According to Rick Congdon, director, landing gear, wheel and brake programs for Nextant Aerospace, the most important thing to look for in a maintenance provider is good in-house machining capabilities. “Otherwise, you’ll have too much downtime,” he said. “That’s what really sets us apart. We can expedite delivery times since we perform all work in-house and have exchange sets available for most of the gear that we support.”
Scott Ingold serves as vice president and general manager of landing gear services for AAR Wheels and Brakes Services, a full overhaul capability station for landing gear, wheels and brakes, servicing all fleets, from military to regional, narrow-body and wide-body aircraft. “With air travel ramping up so quickly this year, the name of the game right now is speed,” he said.
When it comes to maintaining landing gear systems, Congdon notes the important role aircraft operators play. “Most operators are limited just to keeping up with the manufacturer’s recommended routine maintenance, including cleaning, servicing and lubrication,” he said. “The more an operator can keep landing gear clean and lubricated, the better it looks when it comes into the overhaul — and the less will be required.”
Since the COVID-19 pandemic began, Ingold has seen the supply chain for parts fall under strain. “Getting parts from OEM partners is difficult right now,” he said. “Plus, making the decision on when to overhaul the landing gear was easier prior to COVID because operators were flying all their aircraft. In today’s cash-scarce environment, making decisions on servicing expensive landing gear is more difficult. We see operators waiting as long as possible and getting creative when they want to overhaul their landing gear.”
Keeping Wheels and Tires Performing Optimally
Raimond Jacobs is owner of Aircraft & Component MRO, a small, independent maintenance provider for more than 120 different aircraft wheels and brakes. He emphasizes the importance of following OEM instructions when working on wheels and other aircraft components.
“Sometimes we see problems when we are receiving wheels that we didn’t perform maintenance on before,” he said. “Particularly corrosion issues and worn hardware. Then it takes a lot of extra man-hours to correct them or, in the worst-case scenario, to reject a wheel due of exceeding corrosion limitations.”
He adds that the company uses specialized tooling to remove corrosion on hard-to-access areas.
Congdon points out that the loads handled by aircraft wheels make them “one of the most critical components on an aircraft. We must look sub-surface for cracks, voids and corrosion,” he said.
Alex Lara, director of wheel and brake services for AAR Wheels and Brakes Services, agrees. “Wheels are close to the ground, so you get a lot of debris hitting the wheels, deteriorating the protective paint cover on them,” he said. “Manufacturers are always working to come up with stronger paints.”
According to Jacobs, as with every aspect of aircraft maintenance, time is of the essence when servicing wheels. “We also work on many business jets and it seems that the operators don’t have sufficient spare wheels,” he said. “So, they want to do wheel maintenance during their downtime which can be just a few days. We can help them do this.”
Nextant Aerospace’s non-destructive testing (NDT) lab uses the most current methods of NDT, says Congdon, to ensure maintenance procedures are thorough, “including eddy-current, magnetic particle and ultrasound testing, to assure the wheel is serviceable and ready to be put back into service.”
He adds that keeping the wheels and tires from experiencing hard landings, quick stops and unneeded wear and tear are all key to maintaining them well. “Storing spare wheel and tire assemblies out of sunlight and with the proper storage inflation pressure also will prolong the life of the tire,” said Congdon.
Lara added, “Over-inflation and under-inflation will cause early removal of the tire because of damage. Tires should always be properly inflated while in service.”
The Complexity of Braking System Maintenance
Braking system maintenance presents its own unique set of challenges. “Carbon brakes are dramatically different than steel brakes,” said Congdon. “They’re used on most corporate, commercial and military aircraft now being produced. This reduces the weight by at least 60 percent and improves landings between overhaul by 100 percent or more.”
For braking systems, he adds, there is typically a wear pin which provides a visual indicator that it’s time to change the brake. “Maintaining the braking systems falls into two categories — if an aircraft has steel brakes, the brakes are disassembled, cleaned, subjected to NDT testing and, finally, all of the parts subject to wear are replaced,” he said.
If the aircraft has carbon brakes, the same process is involved, “plus, depending on the OEM of the carbon stack, there may or may not be other strategies available rather than just a flat replacement of all of the carbon,” said Congdon.
New technological advances are helping maintenance providers preserve existing parts. “We now have technology that allows us to repair parts and reclaim parts that previously would have been deemed scrap, which leads to lower costs,” said Congdon. “Other advances through the years have been improvements in coating and plating technology, which prevent corrosion. Corrosion and wear are the two things that destroy landing gear components and make them nonrepairable.”
And having the right testing equipment is essential to proper servicing, adds Congdon. “We made the investment in sophisticated test equipment,” he said. “This test equipment provides the ability to put landing gear on a fixture and simulate landing compression loads. We’re using that technology even on the gear that doesn’t require it because we produce a better product that way.”
Repair vs Replacement
When it comes to landing gear maintenance and overhaul, Congdon notes, operators should work with shops that can effectively repair components which otherwise might be deemed scrap and subsequently replaced.
“That’s the best way to get the costs under control,” he said. “If a shop has in-house engineering capabilities, in-house parts manufacturing authority (PMA) and in-house machining operations, you can provide the best package to the customer for an efficient and cost-effective landing gear overhaul.”
Ingold emphasizes the importance of maintaining a robust supply chain for operators and maintenance providers alike. “The sophistication of the supply chain is a value differentiator for an airline because of how complex the repairs can get and how quickly the airline needs them,” he said. “This year, we have gone from flying very little to ramping up a global aviation industry again. It can be a challenge to get inventory ready to feed these operations that are expanding very rapidly.”
