The objective of this Notice of Proposed Amendment (NPA) is to:
- address three safety recommendations addressed to the European Union Aviation Safety Agency (EASA) related to the accident to an Airbus Helicopters EC 225 LP, registration LN-OJF, on 29 April 2016 in Norway:
- by improving the existing provisions and procedures applicable to critical parts on helicopters in order to ensure that design assumptions are valid throughout their service life;
- by amending the Acceptable Means of Compliance (AMC) to the Certification Specifications (CSs) for Large Rotorcraft (CS-29) in order to highlight the importance of different modes of component structural degradation and how these can affect crack initiation and propagation and ultimately fatigue life; and
- by amending the corresponding CSs with regard to the instructions for continued airworthiness (ICA) for critical parts on helicopters in order to maintain their design integrity after being subject to any unusual event;
- harmonise CS-27 and CS-29 with the equivalent Federal Aviation Administration (FAA) regulations, thus reducing the validation effort; and
- reflect the state of the art for small and large rotorcraft certification, thus modernising the existing requirements and being in line with the current good practices.
The proposed amendments are expected to improve safety, have no social or environmental impacts, and provide economic benefits by streamlining the certification and validation processes.