Aircraft

NASA's Quesst to end 50-year-old commercial supersonic flight ban over US

View 6 Images
X-59 in wind tunnel tests
Lockheed Martin
The X-59 being assembled
Lockheed Martin
The X-59's cockpit
Lockheed Martin
Artist's concept of the X-59
Lockheed Martin
Top view of the X-59
Lockheed Martin
X-59 in wind tunnel tests
Lockheed Martin
The x-59 nose-on
Lockheed Martin
View gallery - 6 images

NASA this week marked the 50th anniversary of the total ban of civilian supersonic flights over the United States. The milestone comes as the agency continues with the development of the X-59 experimental supersonic aircraft intended to reintroduce civilian Mach+ service.

On April 27, 1973, the US Federal Aviation Administration (FAA) imposed a new regulation that prohibited civilian aircraft from flying speeds beyond Mach One over the US land mass or territorial waters. The decision came in the wake of the 1968 Aircraft Noise Abatement Act and growing public concern about the effect of military sonic booms over some parts of the country.

Sonic booms are unpleasant and potentially damaging things. Put simply, they are the result of the shock wave that builds up in front of a supersonic aircraft. As the airplane flies overhead, the built-up energy is released as a boom that is loud enough to crack window glass and startle livestock and wildlife.

In view of this, the 1973 prohibition makes sense from an environmental angle, but there was more to the regulation than simple ecological protection. Part of the support for it was from groups who were opposed to supersonic flight on ideological grounds, while others supported it as a way to protect US aerospace industries by spiking the guns of foreign rivals.

Artist's concept of the X-59
Lockheed Martin

By 1973, the United States was effectively out of the race to win the next revolution in air travel, the development of a practical commercial supersonic airliner. The American government had backed several projects by Boeing, General Electric, and Lockheed, but these failed to make sufficient progress and were largely abandoned.

This left the field to the Anglo-French Concorde and the Soviet TU-144, with the Concorde program gearing up for international sales comparable to the boom seen by the introduction of the Boeing 707, pushing subsonic planes into the margins. However, at that time, the US was the world's biggest aircraft buyer and had a huge share of the world's air traffic. That meant that prohibiting supersonic flight in US air space effectively destroyed the market for faster-than-sound aircraft.

The x-59 nose-on
Lockheed Martin

The prejudicial nature of the regulation can be seen in its wording. If the regulation had been based on noise levels, it would have been theoretically possible to address the issue and develop an aircraft that could fly supersonic in the US, but the FAA specifically said the prohibition was based on speed. Whether a plane generated a boom was irrelevant. It still couldn't fly faster than Mach 1.

Today, the prohibition still stands, but times have changed. Since December 31, 2020, the FAA has been committed to regularly reviewing the question of aircraft noise regulations with an eye toward amending the control of civilian supersonic flight. As part of this reconsideration, NASA's Quesst project, in partnership with Lockheed Martin, is developing the X-59 experimental aircraft.

The purpose of the X-59 is to test a new aerodynamic hull and wing design that spreads out the shock wave of the supersonic aircraft and deflects most of it upward instead of toward the ground. Once it's proven its airworthiness, it will be flown at Mach 1.4 over a flight test course rigged with ground sensors and over a number of volunteer communities to assess the sound footprint of the aircraft, which has been compared to a sonic thump rather than a boom.

The X-59's cockpit
Lockheed Martin

According to NASA, this data will be used to determine acceptable sound levels and how these can act as a basis for lifting the ban and rewriting the FAA regulations.

If successful, this would give the green light to companies around the world that are investing in the renaissance of the age of supersonic passenger travel.

Source: NASA

View gallery - 6 images
  • Facebook
  • Twitter
  • Flipboard
  • LinkedIn
6 comments
Smokey_Bear
Hope all goes well, train speeds are catching up to commercial airliners...it's pathetic. We should be hypersonic by now, but good ol government regulations put the kibosh on that.
David F
An elongated Angel Interceptor from Cloudbase.
Nobody
Without the power of fossil fuels, this won't go very far. Slower is more energy efficient.
Nelson Hyde Chick
Even if the sonic boom is aaceptable, it is still going to take a lot morte energy to propel the plane, and we need to be finding ways to reduce the burning of feul, not find new ways to use more.
dave be
Ive been around for a few 'accidental' sonic booms and a set from 9/11 in the US. They're not really unpleasant. And having lived a lot around airports where military jets take-off and land anyway those are far more annoying with their regularity added to the fact that they are still in no way quiet compared to commercial aircraft. Older family was around pre-ban and heard them all the time.

Yea its 'possible' to get cracked windows from a sonic boom, but only if the plane is especially close and the wave focused on that spot. None of my family experienced damage of any type from those. ..and I have a family member that did damage inspections for the military for claims of damage to civilian property so he would absolutely be in a place to know how widespread the problem was.

TBH it would be much better for us to develop actual high speed trains to go across the wide open expanses on their own stracks. Using those instead of our ancient slow ones renting track time from freight carriers would improve far more than adding some Concorde 2.0s for the 1% to get to malibu faster.
drzarkov99
Lovers of high speed trains need to consider this: one mile of track strong enough to withstand trains moving in excess of 200 mph costs over $1M a mile. The US is a big country, so we're talking a network of tens of thousands of miles, or tens of billions of dollars, and that's just for the physical track. We're having a tough time building an electric grid with enough capacity to handle an increased population of electric cars, so expect many more billions spent increasing the power production and distribution that can handle widespread high speed electric trains. We could produce high speed trains that use fossil fuels, which wouldn't require the expensive grid buildup, or we could develop fuel cell powered trains, which is a whole different problem involving distribution of hydrogen, or accepting a modest amount of CO2 production (less than burning fossil fuels) using the more easily distributed methanol, we could used direct methanol fuel cells (DMFC), but even that hasn't been developed in the scale needed.

All of the above doesn't begin to address the issues of routing the high speed rail system through numerous states and municipalities that will have safety and local transport concerns. Just being "green" isn't a magic ticket in the court system. A big windmill project in Oklahoma designed to deliver power to the southeastern states was stopped cold in Arkansas courts due to concerns about the routing of high power lines through state parks, possibly increasing the possibility of forest fires. Reality can suck, and flying overhead is easier than any other form of transport.