Airbus has joined forces with engine manufacturers to seek clarification from certification authorities on the likely airworthiness requirements for open-rotor-powered airliners.

Several engine manufacturers are exploring open rotor engine designs as a possible way to deliver a step-change in operating economics for future airliners. However, Airbus's powerplant chief, Sebastien Remy, wants more clarity from the European Aviation Safety Agency and the US Federal Aviation Administration on certification requirements, to prevent designers heading down blind alleys.

 © Fligthglobal/Tim Becheno-Brown
An artist's impression of an aircraft with open rotors

"Open rotor [powered aircraft designs] are concepts and do not exist so are not covered by any certification rules, per se," he says.

"It is an area that we are addressing with the engine manufacturers to propose to the airworthiness authorities [what requirements they will set] to certificate these types of machines."

While open-rotor airliner configurations have been studied for many years, there are questions about likely airworthiness rules in areas such as engine layout and blade containment.

Remy says that it is important that "we understand perfectly what kind of rules we have to follow" to ensure that any designs being evaluated would be viable from an airworthiness standpoint.

He adds that the lack of airworthiness benchmarks means "there is currently some uncertainty about the true performance of these new concepts".

Source: Flight International