When an aircraft breaks the sound barrier (sonic boom) it is a very noisy event, akin to a shotgun blast or even a small cannon. To anyone near an overflying aircraft that breaks the sound barrier, this event can be shocking or even scary, particularly if they do not expect to hear it. While a sonic boom can rattle the nerves, generally speaking they are not dangerous and should not be a cause of concern.
The sonic boom phenomenon explained
A “sonic boom” occurs when an object, (most often fighter aircraft, but lately SpaceX rocket landings) exceeds the speed of sound, which is approximately 750 miles per hour at sea level. Additionally, supersonic flight is generally conducted at above 30,000 ft. Mean Sea Level.
An aircraft traveling through the atmosphere continuously produces air-pressure waves. A good visualization would be the waves caused by a ships bow cutting through the water – when an aircraft exceeds the speed of sound, these pressure waves combine and form shock waves.
Photo: Congressional Research Service
The “sonic boom” heard on the ground, is the sudden onset and release of pressure following the buildup by the shock waves. The change in pressure caused by a sonic boom is only a few pounds per square foot, similar to the pressure change experienced when an elevator descends a few floors in a building.
According to the Air Force : “ The strongest sonic boom ever recorded was 144 pounds per square foot and it did not cause injury to the researchers who were exposed to it. The boom was produced by a F-4 flying just above the speed of sound at an altitude of 100 feet .”
1 A visit to an airshow
See amazing aircraft and hear a sonic boom?
An airshow is the incredible opportunity to go with family or friends and experience both civilian and military aircraft. Attendees have the privilege to walk on the grounds of an airfield and take a detailed look at the aircraft. While watching the aircraft (particularly the military variety), attendees may have the opportunity to witness a fighter jet break the sound barrier.
Photo: USAF
One such instance occurred at the July 2021 OshKosh Air Adventure in Oshkosh, Wisconsin. While thousands of spectators looked on in amazement, a US Air Force F-16 of the Viper Demo Team, executed a high-speed pass as part of its display routine, this time, it included the production of a sonic boom.
Photo: USAF | Maj. Garret “Toro” Schmitz
While some onlookers were surely frightened, it is important to be prepared to hear a sonic boom if you are in attendance at an air show.
2 Military training
Forget morning coffee, morning boom
Engaging in training is crucial for maintaining or sharpening one’s skills. This is true for activities in the civilian world and particularly applies to the US military; training equals readiness.
Photo: USAF
On Tuesday morning, January 30 of this year, residents of West Valley (a region within the Phoenix metropolitan area), Arizona were unexpectedly treated to a sonic boom, courtesy of the US Air Force. At that time, USAF F-16s from Luke Air Force, home of the 56th Fighter Wing, were conducting routine training.
The culprit was Boeing, which later informed the Illinois state government that pilots were taking one of their new F-15EX Strike Eagle II jets for a “final acceptance’’ flight.
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Officials from Luke Air Force Base acknowledged that the disturbance was under investigation and stressed their commitment to community safety.
Photo: USAF
If you are living near or visiting an area that hosts a military air base, you should be prepared to experience the possibility that its aircraft may break the sound barrier. However, the chances of this occurring are relatively low.
3 Test flights
The Simple testing of military aircraft could generate a sonic boom
In December 2021, residents in central Illinois had their nerves rattled when an unexpected ‘boom’ shook their morning routine and peace. Residents in this area quickly began calling and emailing local police, fire stations and city government offices, with some suggesting it may have been an explosion at a local chemical plant.
Photo: USAF
Moments after the unexpected noise, the Illinois Emergency Management Agency announced that it was working in conjunction with government and law enforcement agencies to identify the source of the thunderous noise, which would turn out to be an F-15 breaking the sound barrier.
4 The landings of SpaceX’s Falcon 9 rockets
SpaceX lands its Falcon 9 rockets at Cape Canaveral Florida
While not a fighter aircraft, yet worthy of mention (as this is becoming a semi-regular occurrence), SpaceX lands its Falcon 9 rockets at the Cape Canaveral Space Force Station on Landing Zones 1 and 2.
Landing these rockets generates a sonic boom during the first-stage reentry, and they have become a common occurrence. Overall, SpaceX has landed its Falcon 9 boosters nearly 400 times since its first commercial resupply mission to the International Space Station on October 8, 2012.
Photo: USAF
In this case, given the regularity of the Falcon 9 landings, residents can expect to hear a sonic boom and not be frightened, unlike the seemingly terrorized residents of central Illinois.
5 Emergency situations
Emergency situations are rare and highly unpredictable
In situations that require immediate response, the Air Force may launch fighter aircraft to intercept a suspicious aircraft or an aircraft that deviates from its flight path without a response.
Photo: NORAD
Such was the case in June 2023, when a Cessna 560 Citation V took off in Elizabethton, Tennessee and lost communication 15 minutes after takeoff.
The Cessna then turned around near New York City and later flew over Washington D.C. This prompted the launching of F-16s, which were authorized to fly at supersonic speeds and deploy flares, according to a statement by NORAD. The sonic boom could be heard in the Washington D.C. region, prompting surprise and concern from residents.
Photo: NORAD
Sadly, the Cessna later crashed near the George Washington National Forest in Virginia after descending at a rate of 20,000 ft. per minute instantly killing all four onboard.
Experiencing a “Sonic Boom”, a stir of emotions
Experiencing a sonic boom can be exhilarating if you expect it to occur, such is the case with an air show or watching a Falcon 9 descend to its landing station at Cape Canaveral. A sonic boom may also be terrifying if it is unexpected, particularly in the morning.
Photo: USMC | Lance Cpl. Seferino Gamez
No matter when it occurs, a sonic boom is generally a harmless event, with an explanation from authorities as to its occurrence making its way to local news outlets, to reassure the public.