EASA is drafting a certification memorandum on fuel tank safety to instruct airframe designers in how to deal with threats from surrounding structures. Most current fuel-tank testing concerns minimizing fuel leaks and potential ignition sources, so the proposed "drop test" is critical.

“It involves a very complicated test, subject of a lot of discussion with applicants; therefore, we are issuing a memo,” structure expert Herdrice Hereson said at the recent EASA rotorcraft symposium.Three options are presented in the memo—testing, analysis and design change—each with its pros and cons.

A certification memo is a not-well-known document EASA publishes to clarify certification rules. “It is for information purposes only, it does not contain requirements, but is rather complementary and provides guidance,” rotorcraft structure specialist Emily Lewis explained. A public consultation phase is part of the process.