to more than 2,000 shp, PT6A engines are currently used by more than 6,500 operators in more than 170 countries. More than 36,000 PT6A engines have been built since this turboprop entered service in the 1960s. PT6As can be found on Beechcraft 1900s and King Airs; Bombardier Twin Otters and Dash 7s; plus a range of Embraers, Piaggos, Pilatus, Piper, and Shorts airframes. Collectively, there is a universe of
turboprop engines in use today. But despite the differences between all of these platforms, the basic turboprop design remains constant in all of its applications—and the unique demands it puts on MROs. “The turboprop contains an output shaft
and delivers power, as opposed to jet thrust,” explains Maria Mandato, External and Marketing Communications advisor at Pratt & Whitney Canada. “Most shop interventions require a post-maintenance test-run to verify the engine power output. Because of this, the MRO provider requires access to a test-cell fitted with a dynamometer suitable for the power range and the engine output shaft speed.” When it comes to performance
measurement, one size does not fit all. A different dynamometer is needed for each specific engine family of turboprop. “The dynamometer also needs to be precisely calibrated,” Mandato says. “This often means that a different engine test-cell is required for each engine family, which can be a significant investment for MRO providers.” In contrast, turbofan engines do not require a dynamometer. Hence a single turbofan test-cell can be designed to accommodate several engine models. That’s not all. “Turboprops tend to
have more special tooling than our turbofan and turboshaft engines,” says Mike Bevans, Honeywell’s director of technical sales. “They also have unique control systems requirements such as prop governors ... our turboprops have hydromechanical control systems which are more demanding to rig and adjust, and more challenging to conduct training for technicians who work on them around the world.” Clearly, turboprop servicing is a
specialized skill in itself; one that requires the right components and knowledge base to do the job properly. This is why MROs interested in this sector would be wise to strike up relationships with turboprop OEMS such as Honeywell, P&WC and Rolls Royce. Not only do such relationships build the necessary knowledge base, but ties to turboprop
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OEMs can also open opportunities for joint projects and service affiliations.
Serving These Needs As turboprop OEMs, both Honeywell Aerospace and Pratt & Whitney Canada (P&WC) provide extensive MRO support on a global basis. The numbers explain why: “We have shipped 13,000 engines in
our TPE331 family over the past 40 years,” says Honeywell’s Bevans. “We actively support those engines worldwide.” Pratt & Whitney Canada is equally
committed to turboprop support. “Our MRO network, which includes several independently owned shops appointed by P&WC, consist of over 14 R&O facilities providing services on our PW100 series
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