Fifty years ago today, on March 23, 1973, Alexander P. Butterfield, the Administrator of the Federal Aviation Administration, issued a rule that remains one of the most destructive acts of industrial vandalism in history.
“No person may operate a civil aircraft at a true flight mach number greater than 1 except in compliance with conditions and limitations in an authorization to exceed mach 1 issued to the operator under Appendix B of this part.”
This text was slightly modified in 1989 and again in 2021, but the upshot remains the same. The rule imposed a speed limit on US airspace. Not a noise standard, which would make sense. A speed limit.
This speed limit has naturally distorted the development of civil aircraft. For fifty years, the aviation industry has worked to improve subsonic aviation. Commercial passenger aircraft are safer and more economical today than they were in 1973, but they are no faster.
If we had propagated the rate of growth in commercial transatlantic aircraft speeds that existed from 1939 to the mid-1970s, we would have Mach-4 airliners by now. But the overland ban put an end to all that. It made small supersonic aircraft, which need to fly shorter overland routes, essentially illegal, closing off the iteration cycle that could drive progress in the industry.
That’s Eli Dourado who notes that modern designs greatly reduce sonic boom. I would also add the following. In 2019 there were 811 million passengers on US domestic flights and 241 million passengers on US international flights. The average duration of a domestic flight is about 2.5 hours and an international fight about 7.3 hours so Americans spend about 3.7 billion hours every year on airplanes. If we could cut even 20% of that time that’s a saving of 757 million hours which has to be weighed against a few people experiencing sonic booms near airports. Indeed, since the people on the airplane are subjected to a lot of the noise the total amount of noise experienced could easily go down with faster aircraft!
