Supersonic business jet developer Aerion has officially launched preliminary design of its 12-seater, Mach 1.4-capable AS2 and revealed ambitions to develop bigger and faster follow-on variants, including potential commercial models.

With prospects for the full launch of the trijet project now seemingly brighter than ever, and conceptual design already completed with industry team partners Lockheed Martin and General Electric, Aerion also reveals that avionics heavyweight Honeywell has joined the group as its flight deck provider.

Detailing progress here at NBAA, Aerion CEO Tom Vice says the AS2 remains on track to fly in 2023 and complete certification in 2025. But with the preliminary design phase for AS2 due to conclude in June 2020, and assembly of the test aircraft beginning shortly thereafter, Aerion already sees the initial business jet as a jumping-off point for a family of supersonic successors.

“The AS2 is the first step on a roadmap to making supersonic travel efficient, sustainable and widely available,” says Vice. “Today we are at the limits of available technology. We are starting with a business jet because the technology closes and the business case closes – we see a viable market for the AS2. It will be our springboard to larger and faster designs, both for business aviation and commercial airliners.”

The company’s confidence in a wider supersonic market stems partly from recent progress by its industry team toward overcoming what Vice describes as “the tremendous challenges in creating a supersonic renaissance.” These range from propulsion, takeoff and supersonic cruise noise and emissions issues to aerodynamic, structural and systems challenges. 

One of the most critical areas is meeting current and future airport noise rules. Despite needing an engine with a relatively large core and low bypass ratio to cruise supersonically, the AS2 is being designed to comply with tougher airport noise limits that take effect for aircraft certified after 2020 and are known as Chapter 14 internationally and Stage 5 in the U.S.

With this legislation looming on the horizon, Aerion began redesigning the aircraft eight years ago and sought a new engine to replace the Pratt & Whitney JT8D originally baselined for the project. According to Vice, the subsequent decision to use a new GE-developed engine in 2017 based on the high-pressure core of the CFM56 is already paying dividends. “We’ve overcome some huge technical hurdles and we’re confident we’ll meet Stage 5 takeoff and landing noise requirements,” he says.

Brad Mottier, GE vice president and general manager for business, general aviation and integrated services, says the move to faster aircraft is the next logical area of advance for the industry. “In the last 50 years, business aircraft speeds have increased by less than 10%. Instead of going faster, cabins have increased in size and become more comfortable – and range has become longer. With large, comfortable-cabin, long-range aircraft in the marketplace, the next step is speed.”

However, Vice notes that future family evolutions will depend on advances in propulsion technology. “Today we are adapting off-the-shelf engine core technology, which in itself is no easy task. For the supersonic industry to progress, we need to demonstrate the market and spur the development of new engine technologies that will meet evolving regulations for noise and emissions, while boosting speed,” says Vice.

“A next generation beyond the AS2, based on further adaptation of current engine technology, could take us from the AS2’s speed of Mach 1.4 to Mach 1.6, and could serve as a larger-cabin, longer-range business jet and small airliner. Entirely new engine designs hold the potential to build larger aircraft able to fly at Mach 1.8 and above,” he adds. “Aerion intends to be at the forefront of these developments.”

For now, the focus remains firmly on the AS2, which is designed to super-cruise at Mach 1.4 over water, but under appropriate conditions could fly over land at Mach 1.2 without the sonic boom reaching the ground. This makes use of the Mach cutoff phenomenon in which the thicker air at lower altitude refracts the boom away from the ground. Design range is 4,200 nm at Mach 1.4 and 5,400 nm at Mach 0.95. 

Honeywell, which is expected to develop a version of its Primus Epic avionics system for the AS2, is also researching displays and software that will enable crews to fly optimal flight profiles to minimize boom potential and maximize Mach cutoff conditions. Carl Esposito, president of electronic solutions at Honeywell, says a role in the AS2 program represents “a fantastic opportunity to pioneer a new segment of aviation with Aerion.”