Lawmakers in the USA have embarked again on an effort eliminate a federal rule that has banned supersonic air travel over land since 1973.
That rule is one of several hurdles facing aircraft developers seeking to bring to market a new generation of supersonic passenger transports.
Senator Ted Budd from North Carolina and Troy Nehls, a House of Representatives member from Texas, have introduced a bill that would require the Federal Aviation Administration (FAA) within one year to allow overland supersonic flights without special permissions.
The bill is being hailed as a potential game-changer by supersonic passenger jet developer Boom Supersonic, which aims eventually to produce its still-conceptual Overture aircraft in North Carolina.
The “Supersonic Aviation Modernization Act” would direct the FAA to “issue or revise regulations, within one year of enactment, to allow for the operation of civil aviation aircraft to operate at speeds of Mach 1 or higher without requiring special authorisation, so long as no sonic boom reaches the ground within the United States”, Nehls’ office says.
Nehls and Budd – both Republicans – are positioning their bill as critical to US security by ensuring US supersonic technology development is not eclipsed by development in China.
Several US companies in past years had been seeking to develop supersonic passenger jets despite the ban, while hoping the restriction would be lifted. Some such start-ups, including one called Aerion, failed amid cash shortages.
But Boom, based in Denver, has endured. It has recently been flying a demonstrator aircraft called XB-1, at supersonic speeds, over California, doing so under a special permit.
The company says the sonic boom generated by its envisioned Overture passenger jet will not be audible on the ground owing to an effect known as Mach cut-out, whereby environmental conditions and the aircraft’s design keep the sound from reaching ground level.
“Supersonic flight without an audible sonic boom should obviously be allowed. The ban on supersonic has held back progress for more than half a century. I urge Congress to pass” the bill, says Boom chief executive Blake Scholl.
Now is not the first time US lawmakers have taken steps to eliminate the ban. A bill proposed in 2017 never got traction.
NASA has also been working on “quiet” supersonic aircraft as part of its Low-Boom Flight Demonstration project. Central to that programme has been NASA’s development with Lockheed Martin of the X-59 Quiet Supersonic Technology demonstrator.
That aircraft had been scheduled to have completed first flight by now, but the project has been delayed, including due to challenges involving flight controls.
