Are sonic booms illegal? A tech geek‘s in-depth look
As an aviation geek, I‘m fascinated by innovations that push the boundaries of flight. Supersonic travel is one of those advances – but legal barriers still exist in the US today around "breaking the sound barrier" due to concerns over sonic booms. In this post, we‘ll dive deep into the science, history and debate around these loud thunderclaps of sound.
What causes sonic booms and how loud are they?
When an aircraft exceeds the speed of sound – about 767 mph at sea level – it creates shockwaves that combine into intense sonic booms. But how loud are these bangs really?
The sound level of a sonic boom depends on the plane‘s size, shape, and acceleration – a larger or more maneuverable craft makes a bigger boom. NASA estimates that supersonic fighters like the F-18 Hornet can produce booms over 200 decibels, louder than standing beside a roaring jet engine. In comparison, the now retired Concorde jet generated a relatively quiet 105-115 decibels during supersonic cruise.
For context on those decibel levels:
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140 dB is the human pain threshold – Concorde‘s booms were far below this
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120 dB is a thunderclap or chainsaw – F-18 booms can match or exceed this
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60 dB is normal conversation – even "quiet" booms are 100x more intense!
No wonder homeowners complained when sonic booms began rattling their walls in the 1950s!
A brief history of the ban on supersonic flight over land
During the post-war years, rapid advances in aviation led to new fighter jets able to easily exceed Mach 1. As supersonic test flights moved over populated areas in the 1950s, sonic booms began impacting bystanders on the ground. By the 1960s, public outcry over being "boomed" regularly led the FAA to declare the situation "intolerable".
With civil supersonic transports on the horizon, legislators reacted. The FAA ceased authorization of supersonic flight over land in 1973, effectively banning future commercial travel faster than sound within the US.
What are the arguments around banning sonic booms?
Keep the ban. Despite not posing a major public health risk, sonic booms are an indisputable nuisance and intrusion on communities in their path. Homeowners certainly don‘t want unexpected bangs rattling their houses! Continuing to prohibit shockwaves over populated areas is a prudent safeguard.
Allow innovation. Today‘s advanced designs can reduce sonic boom noise levels. With smart regulations and flight paths avoiding cities, limited supersonic operations may be possible with minimal community disturbance. The economic and technology gains from supersonic research are too great to ban outright.
My view. We should take a measured approach. Carefully permit testing and development initiatives advancing quiet supersonic travel. But maintain the ban until robust evidence shows booms can be tamed over land. Drastically reducing noise impacts is critical both for public acceptance and realizing supersonic transport‘s potential.
How loud could "quiet" sonic booms be?
While no boom will ever be silent, NASA researchers say innovative aircraft shaping could make them quiet enough to potentially be acceptable for overland flights. Here‘s how designers might shrink boom noise:
| Aircraft | Sonic boom intensity |
|---|---|
| Concorde (baseline) | 105-115 dB |
| Modified Concorde | 95 dB |
| NASA X-59 | 75 dB |
| "Perfect" design | 65 dB |
For comparison, normal background city noise is about 80 dB. So while a "quiet" 75 dB boom would still be noticeable, it reduces disruptiveness considerably.
Could the current regulations ever change?
Possibly, but key challenges remain for supersonic aviation:
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Technological – Improved designs must reliably achieve quiet, soft booms rather than loud cracks. NASA‘s X-59 test plane aims to demonstrate this critical low-boom capability after its first flight in 2024.
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Regulatory – New rules must allow quiet supersonic flight, but with stringent safeguards on boom levels and paths away from homes. This complex balance requires buy-in across industry and government.
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Public acceptance – Will communities tolerate quiet booms for sake of faster air travel? Outreach assessing perceptions will guide any regulatory updates.
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Economics – Do lower sonic boom designs still enable affordable high-speed transportation? Ticket prices will impact consumer demand.
NASA and the FAA continue collaborating closely on these hurdles under the Commercial Supersonic Technology project – but results take time.
For now, patience remains key. As much as I‘d love to fly faster than sound, the existing ban will stay while this pioneering research progresses. But with sustained work, muted "soft thumps" from quiet supersonic jets may one day become a reality!
The future is fast – eventually
Supersonic travel unlocks a world of possibilities. Imagine crossing the US from New York to LA in just 2-3 hours versus a 6 hour slog!
As an avgeek, I‘m thrilled at this future potential. But I also understand communities want smart limits on aircraft noise. With continued innovation and testing, I believe we can find the right balance to enable faster flight.
What does the future hold for quiet supersonic travel and a world more connected than ever? I don‘t yet know, but it will be fascinating to experience! No matter your views on the complex sonic boom debate, we can all agree the joys of discovery move us forward.