Trent XWB turbofan engine: the A350 gets a power boost

Safran has been selected to supply the power transmission system for the Trent XWB, the engine to equip the future Airbus A350 XWB. Olivier Horaist, CEO of Hispano-Suiza (Safran group), discusses just what this program means.

Can you remind us in just a few words exactly what is a power transmission system, and how important is this program for your company?
The power transmission system is used to channel off part of the engine's power in order to distribute it to various other equipment needed for the operation of the engine and of the aircraft, such as the fuel pump and the electric generators. It is a complex and critical system that incorporates over 400 component references spread across several subsystems: internal gearbox, step-aside gearbox, accessory gearbox and oil tank.
Even though we are already one of the two world leaders on this market, this program is somewhat daunting in a number of respects. First of all, this is the first time that an engine manufacturer has entrusted us with the development of the entire system. Secondly, we shall entirely responsible for the activity as a whole - including support - and for the entire lifecycle of the engine, in other words for some 40 years or so! Lastly, this will also be the first time that we'll be providing such a service to such a major fleet. Even before its service launch, over 550 Airbus A350 XWBs have already been ordered, which means over 1100 engines! It is therefore a program of major structural significance for our company.

What does the new system developed by Hispano-Suiza have to offer? How does it testify to the company's capacity for innovation?
If you compare the power transmission performance of the Trent XWB engine with that of its predecessor, the Trent 700, we have improved the weight to transmitted power ratio by a factor of two. As everyone knows, weight is such a key factor in the design of an aircraft, and this result has been obtained thanks to a "Design To Cost and To Weight" approach, which has been applied for the first time by our engineering department in such an "aggressive" way. This has led us, in particular, to seek to simplify parts design, and into the bargain leverage major enhancements in terms of the robustness and future reliability of the supply chain.

What is the development status of this system?
The contract with Rolls-Royce was signed in mid-2008. We delivered the first system in the first half-year of 2010, then three others in the following months. To date, the tests carried out on the first Trent XWB engine since the month of June have confirmed nominal operation of the system. Test will be continued intensively in the coming months, with the first flight testing of the engines scheduled for 2011 (the first flight of the A350 XWB is planned for 2012).