CS-29 Amendment 12 | Reduction in accidents caused by failures of critical rotor and rotor drive components through improved vibration health monitoring systems

The use of vibration health monitoring (VHM) systems to monitor the condition of critical rotor and rotor drive components has been demonstrated to improve incipient fault detection capabilities by complementing those provided by traditional inspection techniques. However, the current acceptable means of compliance (AMC) are not sufficient to ensure that these systems can be certified to be used to optimise the continuing airworthiness for rotorcraft systems.

The regulatory material issued with this Decision identifies ways to certify VHM systems so that they can be a more integral part of the continuing airworthiness process of the rotorcraft and to provide better and updated guidance on the design and operation of these systems, as well as on their effective in-service use. This will result in VHM systems supporting the optimisation of the continuing airworthiness of the rotor and rotor drive systems, thus, reducing the risk of maintenance errors and, potentially, increasing the likelihood of early fault detection.

The amendment to the AMC to CS 29.1465 clarifies the means for establishing compliance where VHM applications are used for airworthiness-related purposes for the rotor and/or rotor drive system. In addition, the guidance provided in this AMC and in the newly developed GM should help to promote the development of VHM systems with improved fidelity and reliability.

With this regulatory material, the European Union Aviation Safety Agency (EASA) addresses the safety recommendation received by EASA (UNKG-2018-007) related to an accident that occurred on 28 December 2016 at the West Franklin wellhead platform, North Sea, UK, involving a Sikorsky S-92A helicopter (registered G-WNSR)

CS-26 Issue 5 | ‘Helicopter crash-resistant fuel systems’ and ‘Information on cargo compartment fire protection capabilities’

Commission Implementing Regulation (EU) 2024/2954 was adopted on 29 November 2024. This Regulation amends Commission Regulation (EU) 2015/640, on additional airworthiness specifications for a given type of operations, and its Annex I (Part‑26) with respect to the following topics that EASA proposed in Opinion No 05/2024:

1. Helicopter crash-resistant fuel systems;
2. Information on cargo compartment fire protection capabilities;
3. Runway overrun awareness and alerting systems;
4. Conversion of Class D compartments;
5. Clarification of existing requirements, including some requirements related to ageing aeroplane structures.

The objective of this Decision is to provide means to show compliance with the new requirements introduced in Part 26 regarding topics 1 and 2 and related guidance material. This Decision also amends some existing means to show compliance with requirements amended in Part‑26 regarding topic 5, and some related guidance material for consistency.

To achieve this objective this Decision amends CS‑26.