Should Airbus and Boeing modify their A320s and 737s to run the fuel-saving next-generation engines currently in development?
At one level, that question is the proverbial no-brainer. Fuel burns roughly a quarter of airlines' operating outlay and the Pratt & Whitney PW1000G geared turbofan and CFM Leap X promise to slash consumption by 15%.
Airbus has it easier with the A320, which has enough under-wing clearance for the new engines' larger diameter fan cases. Boeing would have to work a bit harder on the 737, but both could probably design an improved aircraft for a couple of billion dollars.
Will CSeries be left to fly away with the prize? Not likely
Developing all-new aircraft would cost many times that, and it's doubtful anything short of a radical new airframe concept and extensive use of exotic materials would add much efficiency-wise beyond the gains achievable from better powerplants. No-one believes the technologies needed for a serious airframe advance will be mature for a decade or more. So, for now, the cost and risk of clean-sheet projects look prohibitive, and after their A380 and 787 debacles neither manufacturer has the stomach for a big, risky project.
Some urge caution. Former International Lease Finance boss Steven Udvar-Hazy warns that the new engines are unproven and may not deliver promised cuts in maintenance. And, he argues, increasing the capital cost of aircraft eats away at gains from lower fuel bills.
And, by introducing new models, Airbus and Boeing will hurt the value of the current fleet, which does airlines and leasing companies no favours.
Udvar-Hazy could have added that airframe modifications such as wing strengthening will add weight, undermining the engines' efficiency gains.
With the airline business globally running huge losses and struggling with extreme overcapacity, whatever savings are achieved may mostly be given away to passengers as lower fares by airlines in a desperate battle to fill seats and maintain market share. Any savings that are left would be claimed by hard-pressed airline staff, who've endured job losses and pay cuts.
But such naysaying misses two key points. First, Airbus and Boeing have serious competitive challenges to meet in the A320-737 segment, from Bombardier's PW1000G-powered CSeries and Comac's Leap X-powered C919. Doing nothing isn't an option.
More urgently, innovation isn't a luxury for aviation. Getting better, faster and more efficient has always been the force making air travel possible.