In the absence of feasible propulsion alternatives, gas turbines powering commercial aircraft will remain a key driver of the maintenance, repair and overhaul market for the foreseeable future, a top General Electric executive says.
"All of us are studying hybrids, distributed propulsion," Dale Carlson, executive of advanced engine systems for GE Aviation, told the MRO Americas conference on 3 April. "Boeing and Airbus have shown their green aviation concepts where there are essentially no turbines at all."
While turbines may be eliminated in the future, Carlson adds, the era of turbine-based engines is unlikely to end anytime soon. Simply put, there is no credible alternative on the near-term horizon.
Carlson cites the example of turbine-battery hybrids and all-electric aircraft, currently limited in size and scope to limited batches of light aircraft.
"There'll certainly be hybrids sometime in the next 50 to 75 years," he says.
For now, the energy density provided by batteries for electricity-based propulsion needs to improve by a factor of 10 before it can become a feasible replacement for gasoline combustion in a turbine engine.
When that happens, there are going to be fundamental changes in this industry," says Carlson. "It's going to be massive displacement for all of us that are used to the traditional models."
In the nearer term, pressure from regulation is likely to play a significant role in the move away from traditional turbines. Carlson notes that the controversial emissions trading scheme in Europe is an instigator.
"The [carbon-dioxide] issue is not going away. Through [the International Civil Aviation Organisation] we've all committed to a net 50% reduction by 2050 against a 2005 baseline, despite the fact that growth occurs of a doubling of revenue miles every 13-15 years in the industry. Meeting that kind of commitment is going to take a lot of work on lean-burn combustion, as well as other technologies," he says.