As the business aviation industry matures along with some of the aircraft making up its active fleet, MROs and others are coming up with ways to extend the life of aging business aircraft whose diminished resale value makes engine overhauls cost-prohibitive. “As aircraft get older you can see engine events where to get the engine back into full-flying condition, it’s going to cost more money than the whole aircraft is worth,” StandardAero business aviation division president Marc Drobny told AIN. “So situations like that are really incumbent upon folks like us to come up with options so we can keep the aircraft flying. Otherwise, they’re almost disposable assets at that point.”

A number of alternatives exist to help operators extend the time between overhauls of turbine and turbofan engines through STCs—including those offered by More Company and Sky Aviation Holdings—as well as StandardAero, which is the latest company to join the effort to prolong the need for overhauls. There’s a good reason. According to JetNet, of the 22,500 business jets in the worldwide active fleet, more than a third are 20 years or older. It was one of the factors StandardAero considered in developing its engine exchange program, which lets aircraft owners exchange their engines or purchase replacement engines with lower time to extend the life of their aircraft.

“I think it’s going to be an increasingly important piece of our product portfolio to provide these sorts of exchanges,” Drobny explained. “We’ll probably see it more often in the aged fleet where aircraft values are deteriorating a bit and full investment in a true overhaul is going to add another 800 or 1,000 hours or more to the life of the engine (but) just isn’t in keeping with what the aircraft owner is looking for.”

Other program options allow StandardAero to purchase older engines, enabling aircraft owners to recoup some value, as well as lease engines to owners and operators who choose to do extensive engine overhauls but need their aircraft flying in the interim.

Currently, the program applies to specific engine models—Honeywell TFE731 and CFE738, and Pratt & Whitney PW305—as well as Honeywell 36-100/150 series APUs. But “we definitely will be expanding this into other engine variants over time just as the interest from the market [grows],” Drobny added. A “couple dozen engines and APUs” are currently in StandardAero’s inventory with plans to build that, he added.

Program for Numerous Models

But the options aren’t limited to just those turbofans. Last fall, at NBAA-BACE in Las Vegas, Sky Aviation Holdings affiliate TBO Extension LLC introduced a program for JT15D-5 and JT15D-4 engines that extends their time between overhauls by 2,000 hours through an FAA STC. The program requires a hot section inspection of the engines that is performed by Dallas Airmotive and the installation of engine data recording equipment at one of Signature TechnicAir’s service centers. The program costs $300,000 compared with an average $850,000 bill for overhauling JT15D-5 and JT15D-4 engines, according to the company.

Kyle McConnell of Sky Aviation told AIN that aircraft eligible for the program include the Beechjet 400A, Hawker 400XP, and the Cessna Citation V. It will soon be extended to include the Citation II and Ultra, he added.

Certainly the oldest provider of engine extension programs among the three providers is More (Maintenance on Reliable Engines) Company, which since 1993 has developed eight FAA STCs for multiple variants of the venerable Pratt & Whitney Canada PT6A turboprop engine. The Nevada-based company’s STC and maintenance program is what it calls “aggressive”—more frequent inspections and examinations of certain components and parts of the engine than what is called for by the OEM. But, as More Company general manager Holly Lepire explained to AIN, the idea is to catch issues early and to correct them promptly, which improves engine durability, longevity, and safety. More’s system includes periodic borescope inspections of the hot section, inspections of the compressor and exhaust duct areas, power plant-adjustment tests, spectrometric oil and filter debris analysis, engine vibrational analysis, and preventive maintenance. Its program increases the PT6A’s time between overhaul to 8,000 hours. In the past 27 years, operators in more than 50 countries have used More’s STCs on more than 2,500 engines, according to Lepire.