Overview
Fuel Systems (FS) are critical for aircraft safety. Fire, ice and system failures are typical safety hazards associated to FS. FS accidents, though only representing 2% of accidents/incidents, continue to be a recurrent concern, especially as: the complexity of FS escalades to cope with increasing needs, including more stringent safety requirements; flight conditions evolve with new routes at high altitude, crossing the Arctic, and faster climbing and approach; climate changes with more aircraft (A/C) exposed to hazardous weather.
Thus, FS have to deal with more extreme temperatures, stronger temperature gradients, more humidity, and more exposure to lightning. In addition, new technologies are emerging: Composite, More Electric and Alternative Fuel, bringing new safety requirements. For example, within the composite A/C environment, systems will be more exposed to lightning and induced arcing.
SAFUEL will address the urgent need for European-led research in FS safety to develop the next generation of safer FS also offering the opportunity to reduce the current over-dependence on patented US technology.
SAFUEL will develop:
- The new FS design, meeting the severe safety constraints of Composite and More-Electric A/C and evolving flight conditions
- A range of highly innovative prototypes, adequate testing and simulation tools to allow regulators to assess the safety of future FS as well as providing the necessary data to support authorities in rules and regulations for safe flight in icing conditions
- The project will also significantly improve the compliancy of the FS with evolving flight conditions and emerging technologies, enabling perfect emergence of Composite A/C.
By achieving these objectives, SAFUEL will reduce the rate of accidents/incidents related to FS from the current 2% to 0.4% instead of witnessing an increase. SAFUEL brings together a consortium of best-of-breed experts from academia and industry-from components to airframer.
Funding
Results
Safer aircraft fuel systems
An EU team is studying factors affecting safety in aircraft fuel systems (FSs). The work examines water-related icing in fuel tanks, plus flammability risks, and will yield new data and technologies to meet future FS design challenges.
Aircraft FS failures are relatively uncommon, yet can present an impact on aircraft safety. Furthermore, the growing usage of polar aircraft routes, combined with climate change, could mean an increased risk of FS failure due to icing.
The EU-funded project 'The safer fuel system' (http://www.safuel-FP7.eu (SAFUEL)) aims to develop, test and validate a new, safer fuel system that protects against icing and ignition risk/flammability hazards. The regulation-compliant system will minimise the FS risks associated with future aviation conditions of more extreme temperatures, increased humidity and more frequent lightning exposure.
Technical objectives include improving water detection in fuel tanks, enhancing flammability protection, removing ignition sources and validating compatibility with modern aviation electronics. Additionally, the 13-member project plans to verify compliance with alternative fuel standards. The undertaking runs from September 2012 to February 2016.
In order to develop new technologies, the project first defined an aircraft baseline and multi-level system and component specifications. It also defined criteria on technology maturity, safety and compliance.
Work on the detector for water in fuel tanks began with an analysis of the accident report literature. Hence, an optical dissolved-water sensor is under development. The team tested the ageing properties of optical fibre in aviation fuel, and determined the relation between water detection and temperature. Results indicate good performance of the optical water sensor.
The first stages of studying icing phenomena involved designing innovative test benches to enable the correct modelling of environmental conditions during flights. Subsequently, the team studied various factors affecting ice accretion in inaccessible aircraft locations.
Researchers developed and tested sensor/matrix materials in conditions corresponding to the fuel tank environment. The systems’ requirements led to trade-off choices being made in favour of the most innovative gauging technologies, specifically hydrodynamic-based gauging. SAFUEL also developed and optimised a classical fuel tank inerting system architecture for use with an in-tank oxygen sensor, comparing the energy consumption against a reference architecture.
SAFUEL will yield aircraft fuel systems less vulnerable to the hazards of flight environments. Additionally, the project's innovative gauges and sensor systems represent commercial opportunities for European manufacturers.