This raises an interesting point: the only deficiency pointed to by the AD is 29.863(c)(6):
"(c) For rotorcraft-load combination to be used for human external cargo applications, the rotorcraft must:"
"(6) For human external cargo applications requiring the use of Category A rotorcraft, have one-engine-inoperative hover performance data and procedures in the flight manual for the weights, altitudes, and temperatures for which external load approval has been requested."
HEC Class D being defined (from AC 29-2C) as being:
"Class D rotorcraft-load combination means one in which the external load is other than a Class A, B, or C and has been specifically approved by the
Administrator for that operation (i.e., HEC operations for which the operator is receiving compensation from the person being transported)."
European regulations (JARs) - to this point - have not been concerned with other than CAT; therefore when the HHO Appendix was put into JAR-OPS 3, we were only concerned with CAT - i.e. HEC Class D - and the requirement stated above was contained in that Appendix. (For European HEMS, the requirement that is mentioned in the AD is specifically alleviated for HHO at the HEMS Operating Site (the accident site).)
SAR has been excluded from regulations that specify requirements for CAT (in the UK Public Transport) and each State is left to prescribe its own requirements (this is unlikely to change with EASA Ops). Some States regulate this activity by specifying the CAT requirements and then provide the necessary derogation (from engine failure accountability).
Where this may become interesting is in the area of training; although for some States (the US for example) this area is not regulated under Part 133 - i.e. it can be done without requiring the one-engine-inoperative hover performance, some States do require this protection for the crew members during training.
It is not difficult to understand how this would have happened; most manufacturers would rely upon the wording seen above (rescue hoist = SAR) and not provide the specified data for HEC Class D operations (if it was not specified by the customer). What might be found surprising is that the operator did not ensure this data was included in the RFM if operating in the UK and if the training limitation was still extant.
Jim