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Easy Come, Easy Go: Clean Sky's NextGen Cabin streamlines assembly and reconfiguration

 New Crown Module
New Crown Module

A trio of interrelated next generation cabin design projects from the Clean Sky stable are demonstrating the exciting possibilities of new technologies that make passenger cabins more reconfigurable and assembly line installation processes more streamlined, saving energy and resources for the benefit of European aviation. 

Clean Sky's NextGen Cabin and Cargo Functions initiatives focus on ways to integrate systems and passenger cabin interior architecture that simplify installation procedures on the assembly line, reduce reconfiguration costs, and save time when airlines need to adapt or upgrade the cabin seating and monument layout to respond to changes in capacity demands. 

The main strategy to achieve this is to decouple the cabin and the airframe. Typically, cabin monuments (such as galleys, toilets and bars) are attached to the fuselage frames using brackets for the upper interfaces and via attachments to seating rails that run along the entire length of the cabin floor. A platform concept has been developed which standardises the interfaces between the airframe and the customised cabin and systems components. This will be enabled by the so-called ‘Crown Module’, the upper part inside the fuselage; a ‘Universal Cabin Interface’ (UCI) which concentrates on developing a completely new standardized power and data interface for new aircraft cabins; and a customisable Passenger Service Unit (PSU) – the set of controls above which the passenger sits, equipped with reading light, air gasper and attendant call button. The first and second of these concepts are led by Airbus; the PSU is developed by Safran Cabin (previously known as Zodiac Aerospace).

‘The objective is to try to reduce lead times, create environmental benefits and demonstrate cost reduction through the design, testing and development of highly integrated cabin elements,’ says Clean Sky project officer Jimmy Tchen. ‘The benefits of that relate to enhancing the competitiveness of European aviation by reducing assembly time and the final assembly line lead times. And by doing that you can also help reduce the recurring costs, all in the context of a very competitive industry. There are also environmental benefits as we can expect substantial weight reductions associated with the decoupling of cabin and airframe.’

The Crown Module includes the ceiling area of the aircraft and ‘hat-rack’, and is generally customised, incorporating a wide variety of components.

‘The components in that area can be electrical, but we also have air conditioning, oxygen supply and lots of mechanical fixings,’ says Tchen. ‘All those components have to be individually positioned and assembled, and this is quite time consuming. There's also a lot of interfaces between those components and the primary structures – so the whole idea behind this activity is to try to decouple these parts.’ 

To do this, Airbus is looking at designing and demonstrating a pre-assembled module, before being shipped to the fuselage, to demonstrate that this module can be installed into the aircraft in a single mounting step. This would bring significant cost reduction through quicker lead times. A proof of concept has already been exhibited in Hamburg, and Airbus intends to do a complete demonstrator by the end of 2023.

‘Cabin customisation was not addressed in Clean Sky 1 so it’s quite novel in Clean Sky 2 to address those issues. It's very important from a business point of view for Airbus but there's also benefits of having this included in Clean Sky 2 because you also have environmental impact reduction as well, which supports the competitiveness of the industry as a whole,’ says Tchen. 

The objective of a second activity, the development of a Universal Cabin Interface (UCI), is to create a new standardised and modular power and data interface for cabin modules. Avionics systems in the cockpit benefit from having integrated architecture in the form of standardised interfaces, common hardware modules that are called Integrated Modular Avionics (IMA). The challenge is to bring this approach into the passenger cabin in order to reduce the number of power and data cables, slashing weight and installation times. This will enhance the cabin module operations and optimise the cabin's power consumption through a centralised management system, a concept that also supports the decoupling between the cabin and the airframe.

‘Airbus is looking at two opportunities: A longer term opportunity which is to have a full universal cabin interface that will be implemented in the next generation of single aisle aircraft with entry into service somewhere around the 2030s. And there is also a shorter term possible application for legacy aircraft, where there could be some potential retrofit of these technologies for the nearer term timescale. For that, actually, Airbus is currently targeting a TRL6 by 2021. And that could support an entry into service by 2025,’ says Tchen.

New installation jig for crown module
New installation jig for crown module

Airbus Crown Module and UCI

During 2019, the Crown Module and UCI projects at Airbus progressed with the overall architecture definition and feasibility demonstration thanks to early production of prototypes and integration activities.

‘A cabin modularisation concept was defined – the Crown Module – and a new simplified UCI system architecture developed (for power and data). A tolerance compensating interface was developed to install a customised and system-equipped cabin module in a standardised airframe, and a pre-assembly station and an installation jig were defined. The first prototype of a Crown Module was used for an installation test in ZAL/Hamburg,’ says Christian Hilbck, R&T Project Leader, Airbus Operations GmbH in Hamburg.

Additional achievements include the demonstration of standard power and data interfaces between the cabin monuments and the aircraft with a new power and data network. In the first model of the architecture elements, Model Based System Engineering (MBSE) tools were used to achieve the optimum sizing for different cabin configurations. Currently, an industrial simulation of the complete assembly process is under development using a Digital Twin (Virtual Factory).

‘Altogether this confirms the ability to achieve modularity, scalability and the decoupling principle with the conceived architectural components,’ says Hilbck. ‘This brings flexible and modular cabin architecture which enables faster time to market and performance scalability by enabling cabin functions and performance to be tailored to the customer needs. It also enables the potential to add new functions and new technologies quickly to address future market demands, with the ultimate goal of providing more digitalisation and autonomy to the cabin. This new platform project aims at zero customisation cost in airframe with a maximum cabin customisation, and the decoupling concepts for the standard platform and parts including multifunctional integration enables maximum ramp-up capability to reduce lead-time in the aircraft final assembly line.’

Environmental benefits from the two projects will include a weight reduction of up to 200kg with consequent fuel reduction. By using a standardised method of system architecture and taking a weight-decreasing modular approach, the Crown System will reduce waste through having less scrap, tools, hardware, and less use of raw materials and energy used for design, production and in service. Simultaneously, the Universal Cabin Interface will reduce cabin power consumption, overall weight and CO2 emissions, by using cutting-edge technology.

Universal cabin interface
Universal cabin interface

Safran Cabin's Passenger Service Unit

In the conventional configuration of Passenger Service Units, functions tend to be segregated. For example, the air gaspar, the reading lights, the attendant call button, the oxygen, the signage and seat row indication are all clustered around a single passenger panel. The main idea of the NextGen Cabin PSU is to integrate these functionalities closer together into a more modular unit which is both multifunctional and can also be easily relocated – forwards and aft in the cabin – if required for cabin seating reconfiguration.

‘In order to enable this on the PSU module, Safran Cabin has been evaluating a number of technologies and investigating the use of OLED for lighting and electrical contactless power transmission,’ says Clean Sky's Tchen. ‘In relation to oxygen for drop-down masks the idea is to have an individual and more compact oxygen supply. We can also expect some weight reduction because they are trying to integrate some functions, with the potential to reduce weight as well.’ 

Safran Cabin is working on the PSU design for a future aircraft cabin, documented in what it calls a ‘Platform Compatible Unit (PCU)’ concept – its definition of an optimised PSU unit. The selected concept is also being used as a demonstrator to implement what Safran Cabin assesses to be the most relevant enabling technologies which are investigated in parallel.

The Platform Compatible Unit concept is based on a fully integrated PSU comprising all current required functions plus some additional features, which has also been designed in a way so that PSUs on both the left and right side of the cabin are identical – there is no left-hand/right-hand version, therefore reducing components, part numbers, and saving production costs.

‘A 5 inch display and integrated ambient light together with the wireless communication shall increase the capabilities of the PSU compared to current available PSU systems. The display enables the operator to show customised signs or animated graphics as well as information or commercials,’ says Dr. Lothar Kerschgens, Research & Technology Director, Passenger Service Units at Safran Cabin. ‘The overall passenger experience shall be increased. Maintenance efforts shall be reduced as equipment data shall be available via application on request, and implemented health monitoring means shall support preventative maintenance.’ 

The new concept has been named the ‘Advanced PSU’ since just a few additional features have been added to the Platform Compatible Unit compared to current PSUs. A hardware demonstrator has been built, and some selected enablers and functions have already been implemented. 

Some of the main benefits will arise during PSU production and final assembly. Later on, the CO2 impact will be reduced thanks to less PSU weight. Finally, Dr. Kerschgens says that the PSU as part of the cabin could be produced with ALM 3D printing and pre-assembled outside the cabin: 

‘During final assembly the set of PSUs could be integrated in large cabin segments. This procedure will save a lot of handling time and manual work, and the initial testing and start-up could be time-efficient.’