It seems pretty murky, and there are a number of issues.
1. The CASA regulations at the time
Some people here have stated that carrying a "passenger" is not possible under Aerial Work - that is, the presence of a passenger means the flight must operate as Charter (or RPT).
CASA's NPRM 1003OS July 2010 appears to contradict this view. Section 3 (page 7) makes it clear that passengers can be carried on aerial work flights.
http://www.casa.gov.au/wcmswr/_asset...nprm1003os.pdf
3. Synopsis of Change Proposals
3.1 Purpose of this NPRM
Carriage of Fuel on Flights to a Remote Island – CAO 82.0
3.1.1 The purpose of this NPRM is to consult on a proposed change to CAO 82.0 relating to the carriage of fuel for flights to remote islands. A ‘remote island’ is currently defined as Lord Howe Island; Norfolk Island; or Christmas Island.
3.1.2 Presently, CAO 82.0, subsection 3A requires all passenger-carrying charter flights in aeroplanes to a remote island to carry enough fuel for flight from the remote island to an alternate aerodrome, unless an operator’s operations manual states otherwise.
There are no similar provisions for passenger-carrying aerial work, regular public transport (RPT), private or cargo-only charter flights.
3.1.3 The NPRM proposes an amendment to the Order which will require the carriage of enough fuel for flight from a remote island to an alternate aerodrome for all
passenger-carrying aerial work, charter and RPT flights in aeroplanes, unless CASA approves othewise.
So at the time of writing (6 months after the crash), CASA implicitly stated passengers could be carried on Aerial Work flights.
2. The 2008 CASA audit describes PelAir's AOC on page 2.
http://www.casa.gov.au/wcmswr/_asset...ef12-10004.pdf
To me, this is written a bit loosely. However it seems to suggest that the medivac work was charter. This section continues "AirWork operations consist of target towing for the RAN."
So the last CASA audit prior to the crash seems to suggest air ambulance flights were Charter.
3. The 2009 CASA special audit stated the PelAir line pilots were not sure whether they were operating as Aerial Work or Charter!
4. The CASA email dated 14 April 2010 suggests CASA was not sure what category PelAir's air ambulance flights operated under. Specifically, this email states CASA can not find any reference one way or another, and further that CASA was not aware of any change from Charter to AirWork in respect of air ambulance functions.
This all reads a bit odd, but seems to suggest CASA expected air ambulance flights were Charter (as described in the 2008 audit).
What was going on within CASA at this time? Was someone asking questions why the flight was being considered AirWork?
5. Separate to all these regulations, did the contract between Careflight and PelAir specify a category the flight was to operate under? There may be a distinction between the contractual act of hiring an aircraft (charter), and the Charter category of operation (as defined by CASA). Thus a farmer could contract someone to spray his property for weeds. The farmer could say he was chartering a plane and pilot. But the flights would be Aerial Work.