CS-27 and CS-29 Amendment 4 Issued

CS-27 and CS-29 Amendment 4 Issued

The European Aviation Safety Agency (EASA) has issued Amendment 4 to the Certification Standards for large (CS-29) and small (CS-27) rotorcraft.

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CS-29 Amendment 4 Large Rotorcraft

Agency Decision 2016/025/R on CS-29 Amendment 4 is the result on a rule making process that involved 4 rule making tasks (RMT.0119 (27&29.003), RMT.0134 (27&29.029), RMT.0223 (MDM.024) and RMT.0364 (MDM.089)) and 4 Notices of Proposed Amendment (NPA 2013-21, NPA 2013-04, NPA 2014-16 and NPA 2011-17):

ERASA SC-29 rule making process

CS-29 Amendment 4 introduces the following changes:

  • It introduces provisions on HIRF (CS 29.1317) and lightning (CS 29.1316) to replace previous JAA ‘interim policies’ that have been applied as Special Conditions. EASA say that these “will better reflect existing certification practice” and note that “AMC material associated with these new rules has previously been published by EASA in AMC-20 (the General AMC for Airworthiness of Products, Parts and Appliances) in AMC 20-136 and AMC 20-158 .
  • It also introduces a provisions on volcanic ash (CS 29.1593). EASA says “this will ensure that design organisations undertake an assessment of their product’s susceptibility to volcanic cloud hazards as part of type-certification, and establish limitations and/or information for their safe operation”.
  • It amends the Acceptable Means of Compliance AMC 29.351 on yawing conditions to reflect certification experience and to ensure a consistent and safe approach to establishing structural substantiation.
  • It formally adopts FAA Advisory Circular AC 29-2C Change 4 (published by FAA in May 2014). EASA note that “most changes adopted in this AC were previously developed jointly by FAA and EASA however some minor differences remain”.  These are discussed in the Explanatory Note.  The FAA have issued two further Changes since.

CS-27 Amendment 4 Small Rotorcraft

Agency Decision 2016/024/R on CS-27 Amendment 4 followed a parallel rule making path and resulted in similar changes except of course it adopted  AC 27-1B Change 4 (published by FAA in May 2014, which is now at Change 7), with the caveat of certain minor differences again.


Aerossurance’s Andy Evans is delighted to have been invited to present on Rotor and Transmission Safety at the 10th EASA Rotorcraft Symposium on 6th December 2016, the first to be held in the new EASA offices.


Aerossurance has extensive air safety, certification, design assurance, airworthiness and regulatory experience.  For aviation advice you can trust, contact us at: enquiries@aerossurance.com