The FAA exemption follows the European/ÍCAO model using the graphs provided in Part 2 Section III of the S92 RFM. This originates from the work done on JARs and has been available since the late 90s. It merely allows Bristow to operate as they had previously under other Codes (my guess is that this would be allowed for other applicants).
The AC from CASA is an interpretation of the concepts and text of ICAO Doc 10110 - its contents are well worth reading if you cannot get access to the ICAO Doc.
I haven't read OpsSpec H 305 so cannot comment on its content.
What these references indicate is that most States are now making available the ability to operate in line with the contents of Annex 6, Part III and ICAO Doc 10110 - Helicopter Code of Performance Development Manual; perhaps without actually providing such a code. During the extensive discussions on the subject in the ICAO Helicopter Sub-Group, the FAA representatives always said that, whilst they had filed a difference with ICAO on the contents of Annex 6, Part III, Chapter 3 (i.e. no Code of Performance) because of the difficulty in making changes to the basic regulations, they did regulate through the use of OpsSpecs.
What I previously omitted to mention was that the ICAO based Code of Performance, requires PC1 when more than 19 passengers are carried. The ICAO break points for helicopters are:
PC3 - 9 or fewer
PC2 - 19 or fewer
PC1 - as specified in the Code of Performance or more than 19.
The best document on all of these subjects is ICAO Doc 10110. It may be lengthy but it contains a description of concepts that have been applied world-wide. The only criticism I have of the current document is that it is lacking the comprehensive index it had when it was written, and cross references have been stripped out (navigating in the original was simple). It is not a novel and so should not be read cover-to-cover; it is a reference manual for those trying to understand what a Code of Performance might contain - hence the shame about the lack of an electronic version with cross references.
Last edited by JimL; 3rd Jun 2023 at 05:22.