Nearly two decades since the last supersonic passenger flight, of the British-French airliner Concorde, took off, the planes are set to return to the runways by 2029. United Airlines on Thursday announced it was ordering 15 planes with the ability to travel at Mach 1.7, faster than the speed of sound, from the Denver-based startup Boom.
If the deal gets through, the new supersonic “Overture” aircraft will become the world’s fastest commercial airliner, reducing travel time by about half of today’s planes. Travel time from Singapore to Dubai, usually around seven hours, would be reduced to four hours. United Airlines has committed to buy the Boom planes only if they meet certain requirements of safety and sustainability.
Supersonic vehicles in the past have been flagged for their high use of jet fuels, causing extensive environmental damage. But Boom claims to produce an eco-friendly aircraft with “net-zero carbon emissions”, set to fly with 100 per cent sustainable aviation fuel (SAF).
The announcement of the new technology comes at the time when the global aviation industry is bearing losses due to the Covid-19 pandemic, and a third of the world’s air routes have been lost since 2020.
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Supersonic aircraft are planes that can fly faster than the speed of sound. The technology for supersonic flights is actually over 70 years old, but only recently has been used for commercial flying. Before 1976, when the first commercial supersonic flight took off, the planes were used entirely for military purposes.
Concorde, the British-French turbojet-powered commercial airliner, was the first aircraft to carry passengers at supersonic speed, but eventually had to discontinue, due to cost and other concerns.
Usually, supersonic planes can travel at the speed of around 900 kmph, twice the speed of normal aircraft.
The Overture aircraft would travel at the speed of Mach 1.7 or 1,805 kmph with a range of 4,250 nautical miles. In a single flight, it could carry 65 to 88 passengers and reach an altitude of 60,000 ft.
The company has expressed confidence in getting an “experimental” jet ready by 2022, start rolling out aircraft by 2025 and eventually open them for passengers by 2029. It claims to build on Concorde’s legacy through faster, more efficient and sustainable technology.
The Overture will also not be noisy as supersonic planes in the past were, Boom claims, as it aims for “zero overland noise.” This essentially means that it will cruise at supersonic speeds only over water, ensuring that no sonic boom or excessive noise reaches the surfaces where people live.
Coastal buffer zones will be created into route planning of the airline, enabling the Overture planes to travel over Mach 1 only after it reaches a “safe” distance from the shore.
To be in sync with the global movement against climate change, Boom is aiming high, and is being extremely ambitious, according to experts. Overture planes would rely completely on sustainable aviation fuel, made from biodegradable material. In using this, it aims for maximum fuel efficiency during operations.
Several experts, as quoted in the New York Times, say that such sustainable fuel is currently very limited in its supply, and is extremely expensive. Moreover, the use of this fuel does not eliminate greenhouse gas emissions altogether.
The company also promises to equip the airliner with advanced aerodynamics and carbon composite materials. Through this, it says, it will be able to cut significant development and maintenance costs in ways which the Concorde planes could not.
Flying passengers at a supersonic speed is accompanied by a whole set of challenges. Firstly, the costs of making “sustainable” supersonic planes are extremely high. The very nature of its flying — using excessive amounts of fuel and energy — is likely to have high environmental costs.
Despite the use of sustainable fuels, the greenhouse gas emissions are not nullified. This has been seen in Concorde’s flights, which were terrible in terms of emissions. Not to mention the high amounts of fuel the planes will consume in order to take off, that too in a market where sustainable fuels aren’t readily available. The Concorde used eight times the amount of oil per passenger mile used in a modern day Boeing.
Secondly, the very speed of the planes result in producing excessive amounts of noise pollution in the environment. The “Sonic Boom” created by these planes feels like an explosion to the human ear. This, thus, limits where and when the supersonic planes can fly. They can only reach their actual speed until they are far enough from people and completely over the ocean.
To top these, regulatory approvals to fly such planes can be unsuccessful, especially for transatlantic flights. Getting clearance from regulators around the world would be a challenging task, since the supersonic planes in the past have already been flagged for these hurdles.
Lastly, it would not be economically feasible for everyone. Only the very rich can afford supersonic planes, as a ticket is likely to be way more costlier than a first class ticket of a regular plane.
Supersonic planes flew passengers from 1976 until 2003, making Concorde the first and the last commercial supersonic airliner. The combination of several factors resulted in Concorde’s downfall. Even though it had a high travel speed — twice the speed of sound or 1,512 mph and more than what Boom aims for — it was not economically viable.
The company was not able to keep up with its economic losses. Since it used excessive amounts of jet fuel, the flights became very expensive to operate. Besides this, the planes were let down by a dated system and large amounts of maintenance costs. With over three decades in service, its operational and revamping costs became difficult to maintain.
In terms of passenger experience, there was one common complaint: intolerable amounts of noise. The noise issue prevented other airliners from ordering Concorde planes, stalling its expansion on a large scale.
The high maintenance costs resulted in Concorde tickets costing about $10,000 to travel from New York to London. It also had very limited international routes, as it could operate at supersonic speeds only with certain regulations. The Federal Aviation Administration (FAA) had in 1973 banned any commercial aircraft to travel faster than sound over land.
For many, the high speed was not worth the costs and difficulties experienced during flights. Safety concerns of supersonic planes were also raised after an accident in July 2000, when an Air France Concorde crashed right after takeoff, killing all 109 people on board and four on ground.