Supersonics could return to Northwest. (Jets, not basketball)

It's been more than 15 years since a British Airways Concorde made its final landing in Seattle. The needle-nosed supersonic jet was added to the collection of the Museum of Flight at Boeing Field.

Now, new companies are poised to bring back supersonic commercial flying. A recently-formed industry group wants to designate airspace over the inland Northwest for the flight testing.

Engineering and flight testing contractor AeroTEC leads the new Supersonic Flight Alliance. It aims to attract new business to Grant County International Airport in Moses Lake, Washington. The trick will be to get the Federal Aviation Administration to approve a high-altitude flight test corridor for a new wave of civilian supersonic jets now in development elsewhere.

AeroTEC President and CEO Lee Human said the new designs could make a barely noticeable thump when passing overhead -- not a startling, window-rattling, car alarm-triggering sonic boom like from a fighter aircraft.

"Some equate it to slamming a car door outside of your house where you might perceive it, but it certainly is not going to bother you," Human said during a Friday interview in Seattle. "This is not something that someone is going to believe without data... We want to prove that.”

Human's company, in partnership with the Port of Moses Lake and the Seattle-based industry lobbying group Aerospace Futures Alliance, has sketched out what is basically a 300-mile long autobahn in the sky. The long, skinny rectangle stretches from the east slopes of the Cascades to western Montana, a little bit south of and parallel to the Canadian border.

The advantages of this location include low population density on the ground, good flying weather most of the year and minimal interference with other air traffic.

Human said supersonic flight testing could draw hundreds of jobs to Washington state.

"It's a simple metric to say that for each flight test aircraft, you easily need 100 people to support that flight test airplane," he said.

The Supersonic Flight Alliance has just started its outreach to local civic leaders. It may launch a public relations campaign next year to reassure communities under the potential flight test path.

"I hadn't heard of this yet," state Sen. Brad Hawkins (R-East Wenatchee) said when asked about it Thursday. "My first reaction is to be supportive of industry and new technology so long as it doesn't adversely impact the quality of life of my constituents enjoying their rural living."

Okanogan County Commissioner Jim DeTro said in an interview that he had only heard rumors about the civilian supersonic flight testing possibility, but would keep an open mind given the potential economic benefits to eastern Washington. The switchboard at the county administration has received many citizen complaints over the years about the noise and disturbance that military planes create while training over north central Washington.

The proposal for a supersonic flight corridor came as a surprise to the Confederated Tribes of the Colville Reservation. Rodney Cawston, chairman of the Colville Business Council, said his initial reaction was one of concern about potential impacts to fish and wildlife as well as to people such as vulnerable elders.

"We're not opposed to bringing jobs to rural Washington, but at the same time, we need to look out for our communities and our environment," Cawston said in an interview.

At least three American companies have supersonic passenger planes in advanced phases of development:

• Boeing has invested in Reno-based Aerion Supersonic, which is aiming for a 2024 first flight of its Mach 1.4 business jet. Aerion describes its aircraft as being capable of "boomless cruise."
• Rival Spike Aerospace in Boston has an 18-passenger, Mach 1.6 business jet on its drawing board. It is projected to leave a "quiet boom" in its wake.
• Denver-based Boom Supersonic is aiming bigger. It designed an all-business class, ultra-fast (Mach 2.2) airliner for 55-75 passengers. The design, named Overture, is slated to begin service in the mid-2020s. Boom has signed up Japan Airlines as an investor and potential customer as well as Sir Richard Branson's Virgin Group.

Another potential test range customer could be NASA, which has contracted with Lockheed Martin to build a commercial supersonic demonstration plane. The X-59 QueSST is slated to make its maiden flight in 2021 at Edwards Air Force Base in California. NASA said it wants to measure public acceptance of "low boom" noise in other places during later phases of testing.

Current U.S. rules prohibit commercial and business jets from breaking the sound barrier over land to prevent loud, disturbing booms on the ground. The supersonic flight ban, which does not apply to the military, dates from the days of the noisy Concorde.

Under prodding from Congress, the FAA has begun a rules revision process to open American skies to the new generation of quieter civilian supersonic aircraft. New noise regulations are expected next year. An FAA spokesperson on Monday said the agency deemed it inappropriate to comment right now on the pending proposal for a civilian supersonic test corridor over the inland Northwest.

AeroTEC's Human acknowledged that supersonic flight testing could happen over the ocean or at a military test range. But he noted that civilian manufacturers chafe at the restrictions that come with operating in military airspace. Human said a civil supersonic corridor over land would be preferable because in the case of an inflight problem there would be a nearby airport to which to divert and land a prototype.

The Concorde flew for British Airways and Air France from 1976 to 2003. The sleek planes could cruise at supersonic speeds only while over an ocean or Arctic lands. Noise restrictions, poor fuel efficiency and increasing safety and maintenance concerns combined to force the early retirement of the fleet.

The similar-looking, Russian-bult Tupolev TU-144 made its maiden flight the year before the Concorde, but saw very limited commercial usage. The last of its kind was retired in 1999.

The no-so-super emissions created by supersonic flight add a wrinkle to the sector's revival that the earlier generation of plane manufacturers did not have to confront. It's unclear if this will have any bearing on the location of a civilian test corridor, though.

Public comments from Aerion, Boom and Spike indicate awareness of the outsize impact that high altitude flights in gas-guzzling aircraft could have on global warming. Company leaders say they are working on various strategies to respond, which could vary from fuel-saving technologies and carbon offsets to alternative fuels.