At "all times"? Are you serious? Do these words ("at all times") appear in your ops manual or some CASA rule? Or is this just your interpretation?
They appear in the Qantas Flight Administration Manual ( not my manual).
I think I'll just cut and paste a couple of paragraphs out of the Mildura report in an attempt to make my point clear. I doubt it actually will because some of the posts above quite clearly show a lack of understanding of some common definitions, but here goes.
All of the quotes below are cut and paste from the ATSB's Mildura report.
Qantas issues instructions to it's pilots through a manual that says;
at all times inflight onboard fuel shall not be less than':
• Fuel to proceed to a Suitable Airport;
• 10% of the above;
• Approach Fuel;
• Fixed Fuel Reserve; and
• Special Holding Fuel (when required).
Note: A ‘Suitable Airport' may be, in order of priority:
• the Destination Airport;
• an Alternate Airport, following an approach and missed approach at destination, if the destination requires an alternate; or
• any other Suitable Airport to which an enroute diversion can be made.
Keep in mind that to be a 'Suitable Airport' weather has to be above alternate minima.
So that's QF.
Virgin instruct their pilots through a similar manual, their manual says
Once airborne, the amount of fuel onboard the aircraft at any point inflight should not be less than:
• Fuel required to enable the aircraft to fly from that point to 1500 ft above an adequate aerodrome, make an approach and land; and
• Variable Reserve based on the point above but not more than the Maximum Variable Reserve; and
• Fuel to provide for WX [weather] holding, if the weather at the selected adequate aerodrome is forecast to be below the applicable alternate minima or a probability of thunderstorms is forecast; and
• Fuel to provide for any required TFC [traffic] holding at the selected adequate aerodrome; and
• Fixed Reserve.
In practice that is the exact same policy as QF but expressed with different words.
The ATSB noted this;
The AIP ENR 1.10 paragraph 1.1 had a requirement for a pilot in command to consider forecasts and observation reports during their pre-flight planning. There was no corresponding guidance for application to crews' in-flight planning.
And so did this;
the ATSB sought clarification from CASA on the extent to which pilots are able to use observation reports for in-flight planning decisions, such as to continue to the destination or initiate a diversion.
And CASA scratched their heads for a while before saying that there was
no ‘strategic difference between an in-flight scenario and a pre-flight plan' in relation to the use of forecasts.
And
for in-flight planning considerations the decision making must be based on the forecast element so a pilot must hold an alternate and applicable fuel but is able to make a decision to attempt an approach at the destination should the flight crew calculate additional fuel is available to do so. Specific operator procedures and fuel policies may also need to be considered.
For me, that is quite clear. If I am wrong I am always ready to learn and admit it so I look forward to someone explaining that you can ignore the alternate requirements while airborne, but at this stage I'll keep on putting on gas for the nearest suitable if destination is within cooee of the alternate minima.
PS, if you do have a crack at it, please explain why someone went to the trouble of inventing Special Alternate Minima for use airborne? What advantage would it give if alternate minima isn't used inflight?