‘Son of Concorde’ test pilot reveals update on jet’s first supersonic flight that will blast from London-NY in 3.5 hours

THE XB-1 'Son of Concorde' jet is expected to reach speeds faster than sound for roughly to four minutes in an upcoming flight, its test pilot has revealed.

And civilians on the ground will, fortunately, be spared the deafening sound of its sonic boom.

The supersonic plane, built by Colorado-based Boom Technology, is on track to break the sound barrier in early 2025.

In its first major update of the year, bosses confirmed the jet was able to reproduce "transonic" speeds of Mach 0.95 or 575 knots.

Mach 1 and above is when a jet can be classed as supersonic.

Chief test pilot Tristan “Geppetto” Brandenburg, who has headed XB-1's previous test flights, will be the man inside the cockpit when the next-generation aircraft tops Mach 1 - which is about 767mph.

"Before each flight, I practice several times in the XB-1 simulator," Brandenburg said in a recent .

"It’s a very useful tool to practice airspace and fuel management.

"It also gives me our best prediction of how we expect the aircraft to behave in each new condition."

There are several emergency scenarios that Brandenburg has to run through - such as if the engine fails.

"Finally, we run the profile at least twice with the entire control room: once with the flight going as expected and once with some sort of failure or emergency," he said.

While XB-1’s supersonic flight will last between 30 and 45 minutes, it will only fly at true supersonic speeds for about four minutes.

The actual acceleration from subsonic to supersonic will fairly gradual. 

"A common misconception is that the pilot feels extreme G-forces at supersonic speeds," said Brandenburg. "This is not true."

Once the aircraft is at a steady airspeed, Brandenburg will only feel the force of gravity and the slight pull of acceleration.

That goes for future passengers too.

The XB-1 jet has been authorised to fly in two airspaces: the Bell X-1 Supersonic Corridor and the Black Mountain Supersonic Corridor near Edwards Air Force Base in Mojave, California. 

It's the same airspace where Chuck Yeager became the first person to fly faster than the speed of sound in 1947, in his Bell X-1 plane.

There have been no commercial aircraft capable of supersonic flight since the Concorde - which is why airspace is so limited.

The only aircraft to have reached those speeds have either been experimental planes or fighter jets.

Supersonic aircraft were banned in the UK more than 20 years ago, for a number of reasons, but partly because they were deemed too noisy.

The US banned them even earlier, in 1973, as the sonic booms were so loud they made people's windows rattle.

But technological advancements appear to be wiping out the dreaded sonic boom.

"XB-1’s first sonic boom at Mach 1.1 probably won’t reach the ground," according to Brandenburg.

"We plan to fly at 34,000ft., so the energy will likely dissipate over the roughly six vertical miles between the aircraft and the ground."

It's unclear when the next test flight will be.

At supersonic speeds, the XB-1 jet could feasibly fly passengers from London to New York City in just 3.5 hours.

The flight currently takes roughly 8 hours on a standard commercial carrier.