A NIAR technician performs a non-destructive inspection. Non-destructive testing plays an important role in keeping aging aircraft flying.
“For MROs, this means that they have to do a lot of work on these older aircraft looking for cracks, corrosion and fractures.” That’s not all. “Since most older aircraft have surpassed their DSG maintenance inspection threshold, the aircraft have to be inspected more frequently,” says Lenz. This adds to an aging aircraft’s operating costs. So does the need to replace older parts approaching end-of-life; again not an issue on a newer aircraft.
Jean-Marc Lenz, SR Technics’ SVP of Aircraft Services
The rule of thumb: “The older the aircraft, the higher the potential risk to encounter severe structural findings while performing fatigue tests.”
Put these factors together, and one can see why MROs cannot offer ‘fixed cost per flight’ maintenance on aging airframes. “They just cannot predict what kind of work an old airframe aircraft might require to keep it airworthy,” Berger tells Aviation Maintenance. “As a result, they can’t cost out a safe price that makes them money while providing the customer with affordable maintenance over time.” As for engines? Even though they can
theoretically be kept running forever, in practice this isn’t the case. “Engines tend to boil down to the economics of operating them,” explains Menard. “Increased costs of fuel and costs of maintenance due to reduced competition in the marketplace and availability of parts usually make engines uneconomical—and the residual
hull value of the older airframe rarely is enough to justify the costs of a re-engining upgrade for the fleet.” Sourcing airframe and engine parts
doesn’t present too much of a challenge for MROs. OEMs are generally providing components for these aircraft, or life- extending upgrades that bring 737 classics up to 737 Next Generation lifespan levels. Meanwhile, the number of older aircraft parked in desert holding areas provides a pipeline of recycled parts that can be put back into service. Where supply problems do occur is in the area of electronics and onboard systems. “Electronic parts can be hard to find as technology advances rapidly; and some basic technologies are no longer available in production to incorporate in the manufacture of replacement components,” says StandardAero’s Menard. As a result, “Avionics and cabin management systems’ obsolescence issues are the main challenge in maintaining aging aircraft.”
Even when a carrier has an economic case to keep flying older aircraft, like 727s converted into freighters in underserved areas, where customers are willing to pay top dollar for access, “it can be difficult to find sheet
Aviation Maintenance |
avm-mag.com | April / May 2012 37
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