There is no law that says you must not operate outside the limits of a chart. Can you point me to any such law ?
Now, I'm just an average old pharte pilot and aero engineer, not a lawyer in any sense of the word.
However,
(a) the Act [98 (3)] talks about the Governor General's having the power to make regulations for or in relation to the following
(b) [(h)] goes on to say empowering CASA .. to give or issue directions or instructions ... with respect to matters affecting the ... operation ... of aircraft
(c) [(ka)] provides for requiring the production/amendment of flight (and other) manuals
(d) [(kd)] talks about requiring specified persons to comply with such manuals, systems and documents as in force at a particular time or from time to time
(e) CAR (1988) 2 gives some pertinent definitions -
gross weight, in relation to an aircraft at any time, means the weight of the aircraft, together with the weight of all persons and goods (including fuel) on board the aircraft, at that time, estimated in accordance with the method set out in a direction in force under subregulation 235(1).
maximum landing weight, in relation to an aircraft, means the weight set out in the certificate of airworthiness of, or the flight manual for, the aircraft as the maximum landing weight.
maximum take‑off weight, in relation to an aircraft, means the weight set out in the certificate of airworthiness of, or the flight manual for, the aircraft as the maximum take‑off weight.
It follows that the AFM regulated weights would be captured as well as the TC weights - see CAR (1988) 235.
(f) CAR (1988) 54 talks more about flight manuals
The registered operator of an aircraft must ensure that the aircraft’s flight manual is at all times appropriate for the aircraft, having regard to:
(a) any direction issued by CASA relating to the flight manual; and
(b) any modifications to the aircraft that would require amendment of the flight manual; and
(c) any instructions in relation to the flight manual from the holder of a type certificate, supplemental type certificate or modification/repair design approval that applies to the aircraft
(g) CAR 233 (b) has this to say -
the gross weight of the aircraft does not exceed the limitations fixed by or under regulation 235 and is such that flight performance in accordance with the standards specified by CASA for the type of operation to be undertaken is possible under the prevailing conditions
(h) CAR 233 (c) adds this -
any directions of CASA with respect to the loading of the aircraft given under regulation 235 have been complied with
(i) CAR 235 is the catch all, I think ..
(1) CASA may, for the purposes of these Regulations, give directions setting out the method of estimating, with respect to an aircraft at anytime:
(a) the weight of the aircraft, together with the weight of all persons and goods (including fuel) on board the aircraft, at that time ...
(2) CASA may ... give directions setting out the manner of determining, with respect to a proposed flight of an aircraft:
(a) a maximum weight, being a weight less than the maximum take‑off weight of the aircraft; or
(b) a maximum weight, being a weight less than the maximum landing weight of the aircraft;
that the gross weight of the aircraft at take‑off or landing, as the case may be, is not to exceed.
(2A) A person must not contravene a direction under subregulation (1) or (2) ...
(3) A manner of determining a maximum weight referred to in subregulation (2) shall be such as to take into account such of the following considerations as CASA considers appropriate:
......
(d) the meteorological conditions at the aerodrome at which the aircraft is to take off or land;
(e) the altitude of the aerodrome at which the aircraft is to take off or land;
.....
(g) the material of which the surface of the aerodrome in the direction in which the aircraft is to take off or land is constituted and the condition and slope of that surface
......
(4) The pilot in command of an aircraft must not allow the aircraft to take off if its gross weight exceeds its maximum take‑off weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the take‑off, that lesser weight.
.....
(6) The pilot in command of an aircraft, must not land the aircraft if its gross weight exceeds its maximum landing weight or, if a lesser weight determined in accordance with a direction under subregulation (2) is applicable to the landing, that lesser weight.
Presuming that the typical pilot is, indeed, familiar with the CAO 20.7 series, one should have a look at the following CAOs which cover the bulk of operations ...
(j) CAO 20.7.1b which talks about elevations and ambient temperatures
(k) CAO 20.7.4 which talks about pressure heights and temperatures.
I think you should be planning on co-opting the services of very good Counsel in the event that you are challenged in Court regarding your philosophies ...