October 13, 2023, ©. Leeham News: We are discussing the Detailed design phase of an airliner development program. We have discussed program management methods, development techniques, tools for Detailed design, that improved production methods are as important as improved technology, and that the interaction with the suppliers is key.
But another consideration that affects detail design is the influence of the Certification process. Certification has a major influence on the program work in every step of the aircraft program.
The design and later production and operation of a new airliner are influenced in a major way by the need to adhere to the certification rules of the country where it’s registered and operated. Each country has its own regulator at which the operator must seek authorization for the design, production, and operation of the aircraft.
In practice, we have a few leading regulators like the US FAA and EU EASA, on which local regulators are encouraged by ICAO to base their certification rules, with local adaptations. An airliner OEM must seek certification in each jurisdiction where it wants to sell and operate the aircraft.
As the achievement of global (FAA and/or EASA) and local certification is so important, a new airliner program is adapted to the certification process and its needs.
Here is a summary of what’s needed and must be done;
As the certification part of an airliner project is of critical importance, the OEMs establish special certification line organizations that maintain and develop the knowledge around certification in the jurisdictions where the company’s airliners are sold and operated. A new airliner program then creates its own certification organization that draws its personnel from the company’s line organization.
It’s not only the design certification that affects the airliner Detail design. If the designers want to use a novel technology like thermoplastic composites instead of the established thermoset method, it has to ensure that the method and its design and production rules and processes are mature enough so that they can be accepted by the regulator, not only for the OEM’s home jurisdiction but in every country it intends to sell and operate the aircraft.
I have several times discussed new and improved methods for the production of, for instance, carbon composite parts, only to be informed, “Yes, it’s all interesting and what we want to use, but we have not achieved acceptance for the design “allowables” (i.e., design rules), so this method can’t be used for the project.”
You could say, “Certification rules a project like nothing else.”