Research on certification requirements for the integration of LH2-tanks into aircraft structures

Abstract

Hydrogen represents a bright potential for a carbon-neutral future. For this reason, the aviation industry is engaged in researching how to integrate the new energy carrier for future hydrogen drives into the aircraft structure in an efficient, cost-optimised and safe way. Focusing on achieving the best possible tank volume and weight for use in commercial aviation, the current aim is to store the element in its liquid state (LH2) (at approx. -253 °C, atm). However, this implies, in particular, new hurdles for the existing aircraft architecture, a challenge the German Aerospace Center (Ger. Deutsches Zentrum für Luft- und Raumfahrttechnik, DLR) has decided to face. Precisely for this purpose, the HYTAZER project was launched at the beginning of this year to develop solutions concerning all certification-relevant issues for the operation of hydrogen tanks. Based on identified requirements for the structural design of an LH2 tank, the present thesis evaluates, in essence, where existing requirements of aviation legislation for the installation of hydrogen tanks in the aircraft structure must be supplemented, adapted or can be adopted. These certification regulations for an aircraft are part of the Certification Specifications of the European Aviation Safety Agency (EASA). Completing the literature research (CS 23/ CS 25), it was possible to identify existing standards from other mobility sectors and their experiences with integrating LH2 tanks. Therefore, the work achieves initial findings for the structural design of an LH2 tank in the aircraft structure, such as considered load factors or design pressures to be applied. It thus provides a first fundamental building block for the impulse project launched by DLR - as well as for the aviation of tomorrow.