4 Myths About Supersonic Flight: What Pilots Actually Feel At Mach 1

Supersonic flight and its visions of high-speed thrills, intense pressure changes, and dramatic sonic booms have persisted across pop culture for decades now. But is it legit? While the idea of supersonic flight often conjures up images of cockpit-shaking turbulence and extreme G-forces, the reality is far more nuanced. Yet, over the years, movies, TV shows, and other media have perpetuated plenty of misconceptions about what actually happens when a pilot breaks the sound barrier.

To separate fact from fiction, let's consider some real-world insights from Chief Test Pilot Tristan "Geppetto" Brandenburg, who has extensive experience preparing for supersonic flight with the Boom Supersonic XB-1, alongside retired airline pilot Captain Richard Levy, a 41-year veteran on the job. Their firsthand knowledge provides a grounded perspective on what pilots really experience when accelerating past Mach 1. Let's take a closer look at some of the most common myths about supersonic flight and uncover the rarely-told truth behind them.

One of the most enduring myths about supersonic flight is that pilots experience extreme G-forces once they break the sound barrier. The idea of being slammed back into the seat as the aircraft accelerates may make for great cinema, but it doesn't reflect reality. As Chief Test Pilot Tristan "Geppetto" Brandenburg clarified to Boom, "[It's] not true. Once the aircraft is steady at a given airspeed and not in a turn (unaccelerated), I only feel the force of gravity (1 g). Acceleration in the x-axis (the direction of thrust) is noticeable but far less than even 1 g."

Captain Richard Levy echoed to SlashGear that pilots do not experience excessive G-forces simply because they reach supersonic speeds. As he told us: "Whether flying subsonic or supersonic, G-forces are normal, unless the pilot rolls the aircraft into a steep bank (turn) and/or rapidly activates the 'after burner.'"

In other words, supersonic flight doesn't inherently impose high G-loads on the pilot. The forces involved in high-speed turns or rapid accelerations can create additional G-loads, but simply flying past Mach 1 is not an especially forceful experience. In fact, catapult launches from an aircraft carrier generate far greater G-forces than cruising at supersonic speeds.

Another widespread belief is that crossing the sound barrier results in a sudden, jarring shock, almost as if the aircraft is punching through an invisible wall. This myth stems from early aviation history when pilots in high-speed aircraft reported unexpected turbulence or control issues near Mach 1, leading to the term "sound barrier."

However, as Tristan Brandenburg explained, "The actual acceleration from subsonic to supersonic is fairly gradual. There is a phenomenon known as the transonic drag rise, in which the drag on the aircraft increases sharply at a certain Mach number. Every aircraft has a drag divergence Mach number. For aircraft not designed for high subsonic flight, this can be as low as Mach 0.8."

Captain Richard Levy told us that from inside the cockpit, there is no sudden impact or shake. "Noise is not an issue during the mission (training or actual) whether flying under [the speed of sound] or above [supersonic]." The idea that breaking the sound barrier causes turbulence or instability is a relic of outdated aviation lore rather than an accurate description of modern flight dynamics.

The idea that every supersonic flight produces an earth-shaking sonic boom that rattles windows below is yet another common misconception. While sonic booms do occur when an aircraft exceeds the speed of sound, the exact impact of that boom depends on multiple factors including altitude, speed, and atmospheric conditions.

"XB-1's first sonic boom at Mach 1.1 probably won't reach the ground. We plan to fly at 34,000 ft., so the energy will likely dissipate over the roughly six vertical miles between the aircraft and the ground," Tristan Brandenburg told Boom. 

That means that, at higher altitudes, the energy of the sonic boom disperses before it can significantly affect people on the ground. To put it another way, not every supersonic flight results in a noticeable boom at surface level. In fact, supersonic corridors like those used for testing are specifically chosen to minimize the impact of sonic booms on populated areas.

Many assume that flying supersonically requires constant, intense effort to maintain control, with the aircraft on the verge of instability. This myth likely originates from early supersonic test flights when aircraft designs were still evolving, and pilots had to contend with unpredictable aerodynamic effects. In reality, modern supersonic aircraft are designed to handle well at high speeds. Tristan Brandenburg told Boom, "In preparation for flying XB-1, I flew the F-104 with Starfighters International in Florida. Our models indicated that XB-1 would handle most similarly to the F-104 with the SAS off. One of the key takeaways from that flight was that pitch control became extremely sensitive during the transonic acceleration."

While there are unique aerodynamic challenges, such as pitch sensitivity and changes in trim, supersonic aircraft are engineered to maintain stability. Pilots train extensively in simulators and in comparable aircraft to ensure they are prepared for these nuances. The result is a flight experience that is far more controlled and predictable than many imagine.

Captain Richard Levy confirmed: "There is absolutely no change in the feel of the flight controls whether flying just below the speed of sound or just over the speed of sound, as well as no change of sound within the cockpit when flying in excess of the speed of sound. In fact, the only way a pilot knows they are flying supersonically is by observing the Machmeter."

Supersonic flight remains one of the most fascinating frontiers of aviation, but misconceptions about its challenges and sensations persist. Contrary to popular belief, pilots do not experience extreme G-forces, nor do they feel a violent "sound barrier" shock when passing Mach 1. Sonic booms are not always heard on the ground, and modern supersonic aircraft are stable and well-controlled in flight. Beyond this, ongoing advancements in technology are paving the way for a more cost-effective supersonic travel industry.

As the world continues advancing its supersonic technology, understanding the realities of high-speed flight will become even more important. Pilots like Tristan "Geppetto" Brandenburg and Captain Richard Levy give us the valuable insights we need to demystify the whole experience. Whether for military applications, research, or the future of commercial aviation, it's increasingly clear that breaking the sound barrier is not nearly as much about brute force as pop culture makes it seem.