> The companies working on supersonic jets are in process of lobbying hard to get FAA approval for exemptions from noise regulations. [1]

Note that Boom _isn't_ focusing on noise currently, unlike the other companies (which are much more focused on bizjets), knowing this will limit the routes they can fly on even with any regulatory changes.

They're content to start with just the oceanic routes (and notably they're aiming for longer range than Concorde, and able to fly at least some trans-Pacific routes non-stop); presumably future iterations when it's known whether there will be regulatory changes (and what they'll be) could aim for lower noise and overland flight.

Even if they get an excemption, affected people will probably come with pitchforks and torches to the headquarter. These supersonic booms are really loud.

"Even if they get an excemption, affected people will probably come with pitchforks and torches to the headquarter. These supersonic booms are really loud."

Agreed.

I grew up near[1] the Air Force Academy in Colorado Springs and I have a very distinct childhood memory of some cadet breaking the sound barrier over our town.

I was (figuratively) knocked out of my bed. It was unbelievably loud. I thought the world was ending.

To be fair, this was probably a very low altitude flight so it was probably much worse than a "normal" sonic boom.

Still...

[1] Canon City, CO

I grew up under fairly constant sonic booms. They always seemed pretty cool because it meant a high performance aircraft was overhead. I'm sure they annoyed some people. They excited some people. And they just became mundane to a lot of people.

Are you confusing sonic booms with regular loud aircraft? Sonic booms over land are illegal in most countries. The US military only ever does supersonic exercises far offshore.

I'm not the person you are replying to, but there is a possible explanation if the person is American. In 1964 the FAA organized an experiment to perform supersonic fly-overs of Oklahoma City over a period of 6 months. Quoting from Wikipedia "the experiment was intended to quantify the effects of transcontinental supersonic transport (SST) aircraft on a city, to measure the booms' effect on structures and public attitude, and to develop standards for boom prediction and insurance data."

Link to the wiki page if you are curious

https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests

Here are some highlights

- The US Airforce performed ~8 booms per day between 7am and the afternoon

- In the first 14 weeks, 147 windows in the city's two tallest buildings were broken

- An attempt to lodge an injunction against the tests was denied by a district court judge, who said that the plaintiffs could not establish that they suffered any mental or physical harm and that the tests were a vital national need

- Testing was paused for a time when activist groups sought a restraining order against the testing

- The Saturday Review published an article titled The Era of Supersonic Morality, which criticized the manner in which the FAA had targeted a city without consulting local government

- All this public pressure ended the testing early

- There were 9,594 complaints of damage to buildings, 4,629 formal damage claims, and 229 claims for a total of $12,845.32, mostly for broken glass and cracked plaster.

> There were 9,594 complaints of damage to buildings, 4,629 formal damage claims, and 229 claims for a total of $12,845.32, mostly for broken glass and cracked plaster.

That doesn’t seem much money. Even with inflation which makes it $110,600ish it seems very reasonable. I can imagine one difficult window install making up this much.

I also grew up with constant sonic booms. There is no way to mistake a loud aircraft for them. This is like mistaking a loud engine with a gun shot.

I grew up in Germany, and whatever the laws said (probably sonic booms were illegal), they didn't apply for the allied troups (mostly British and American in my region). So jet fighters going supersonic pretty close to the ground were a rather common thing, you might hear one once a week or so.

(Technically, Germany became only with the 2+4 treaty in 1990 a fully souvereign nation, formally ending the occupied state after WW2)

The U.S. military does supersonic flights over land, too. For example, see page 39 of the R-2508 Complex Users Handbook[1], the section titled "Supersonic Operations". The R-2508 complex[2] is an airspace around the area of Edwards Air Force Base in California.)

1. https://www.edwards.af.mil/Portals/50/R-2508%20User%27s%20Ha... 2. https://www.edwards.af.mil/About/R-2508/

Yeah in France we have them too, I live not too far from Mirage/Rafale air bases, and they fly over sometimes. I remember it was more common around the 2000s, nowadays I hear it less than once a year. I think it happened over Paris last year and people freaked out, calling for a bomb and everything.It was for an interception mission.

https://www.nytimes.com/2020/09/30/world/europe/boom-noise-r...

I remember hearing sonic booms while on holiday in wales as a child, just looked it up and it looks like a couple still happen every year

I assume the military can decide to be exempt from the law if they want

They can in the UK. Back in January, the QRA Typhoons chasing an unresponsive aircraft back in January went right overhead at 10000 ft at supersonic speeds. That was loud: https://www.cambridgeindependent.co.uk/news/huge-sonic-boom-...

I grew up in a remote part of northern California, and I can assure you that every so often a military jet would would fly right over our house at super sonic speeds(and very low altitude, barely above the tree tops).

It was mind numbingly loud and obnoxious-the entire house would shake and rattle and you couldn't hear anything but the rumbling.

I sincerely doubt the jet in question was flying at supersonic speeds right above tree tops. Couple of reasons, at low altitude most military jets can only handle mach 1.2 or so at the cost of massive fuel consumption. Any sort of long distance flight at low altitude, supersonic speeds would waste massive amounts of fuel. Additionally all aircraft are significantly less maneuverable at supersonic speeds which is a bad combination with being close to the ground. Lastly and probably most importantly sonic booms are really really loud. As in they can at least in theory kill people if in close contact(not aware of this actually happening at any point, but there was a cold war project to use a low flying supersonic aircraft as an anti-tank weapon). Point is if they actually where supersonic I would be surprised if you didn't have some form of hearing damage. Also shaking and rattling is not consistent with a sonic boom, just normal jet noise.

It happens accidentally from time to time. It's easier to do (accidentally or on purpose) in some planes, and engine-variants than others.

They are not looking for the ability to cause sonic booms, they are looking allow supersonic planes that don’t produce the concussive booms.

> In the airline industry’s current tube-and-wings model, shock waves largely roll off and then meld into a sonic boom. The aerodynamic X-plane, however, is designed to scatter multiple shock waves and minimize their cumulative effect, producing only a rumble or soft thump. [1]

> Acoustic engineers have developed a system for measuring sonic booms, called perceived levels of decibels, or PLdB. A decibel (dB) is a measure of pressure; PLdB is what people actually hear. When the Concorde airliner went supersonic, its window-rattling booms scored a PLdB rating of 102, equivalent, for a split second, to the high whine of a fighter engine just feet away. Those are the booms that inspired the original FAA ban. The X-59 has been designed to achieve a PLdB of 75, similar to what might be heard when standing next to a heavily trafficked road. (The numeric drop is larger than it might seem; the decibel scale is logarithmic.) In more conventional units, the Concorde’s supersonic sound waves carried a powerful maximum atmospheric overpressure of two pounds per square foot. By contrast, the X-59’s would exert 0.3 pounds per square foot on the eardrum. [2]

[1] https://www.nasa.gov/aero/nasa-prepares-to-go-public-with-qu... [2] https://www.airspacemag.com/flight-today/lower-the-boom-1809...

Let's see how this plays out. They say volume is a key factor, and the test vehicle is very small, while the plane later will be much larger.

> They claim improvements in fuel efficiency and their unique selling point (apart from the speed advantage) is the use of "green" fuels (whatever that implies). Also, see previous point: they don't want to be mainstream anyway.

That seems a logistical issue to me. Airport fueling services have Jet A/A1. So airlines buying Boom will have to arrange contracts to supply these "green" fuels at service destinations?

They've been using Prometheus Fuels (a YC-backed company with further investment from US DOE and BMW i Ventures) thus far, starting with a 2019 deal. It will probably be up to United as to how they fuel the aircraft once in service, but they are basically touting that it is using a carbon-neutral fuel source all through R&D and Prometheus is using Boom to show that it can produce A1 (or possibly JP-8 with additives) in some new ways starting with ethanol and renewable energy sources.

https://www.globenewswire.com/news-release/2019/06/18/187048...

https://www.greencarcongress.com/2020/09/20200916-prometheus...