Sonic booms are the whole problem with supersonic airplanes. And with stringent regulations prohibiting flights at airspeeds in excess of Mach 1 on the books for decades now, the FAA’s stance on the subject has been unequivocal. Until now, that is.
The agency has published a notice of proposed rulemaking (NPRM) laying out two things—one, the certification standards for supersonic aircraft and, two, the procedures that manufacturers would need to get in order to get permission to conduct fight testing.
In the NPRM, the FAA lays out the history behind supersonic flight which, practically speaking, is the history of Concorde, one of only two production supersonic commercial aircraft in history, and the only one that had any measure of success. Still, Concorde was prohibited from going past Mach 1 over land, so its missions were restricted to overwater flights, where it could happily do its Mach 2 thing before turning down the wick and landing at its coastal destination. The whole thing was spectacularly inefficient, and the program getting shut down by British Airways and Air France early in the 2000s was as much, if not more, about the economics of the operation than about the catastrophic crash of one of the supersonic airliners in 2000, after hitting debris on the runway in Paris and catching fire before crashing shortly thereafter.
In that time, the FAA has become convinced that things have changed, that technology has advanced to the point that lighter aircraft with far more fuel-efficient engines can make supersonic passenger airline service a practical thing.
But it’s a different hoped-for advance, the taming of the sonic boom, which numerous companies, as well as NASA, have been experimenting with since before the Concorde program was put on ice.
As part of its proposed plan, the FAA would also revisit its rules every couple of years in order to allow its regulations to keep pace with technological developments.
The list of challenges to a successful supersonic airliner is long, and none of the hurdles is an easy one to clear. So while the FAA proposal would allow flight testing of such projects, it would still be no guarantee of ultimate success.