EDTO fuel - variable reserve at CP?
Could I please ask the group for your thoughts on an issue WRT the use of contingency fuel/variable reserve on an EDTO flight plan?
Picture an A330 EDTO 180 minute flight with a few EDTO segments throughout a 10-hour flight. The final segment, with the destination is one of the final EDTO alternates. The last segment has closely-intersecting 180-minute circles and the ETP between the final alternates is a CP (fuel critical).
The computer flight plan indicates that the critical fuel scenario on this final segment is 2 engines operating, 10000’ depressurised. The excess fuel available at the Critical Point (CP) to accommodate the critical fuel scenario is zero, and, on the specific flight plan I am using as an example, an extra 4500kg is carried as EDTO “build-up” to bring the available fuel up to that required for diversion at the CP. This would be a “normal” EDTO flight planning scenario on the route.
I have noticed that in the fuel flight plan, the variable reserve (some call it contingency fuel) of 2000kg (capped) is part of the fuel available at the CP. I am informed by the training system that it is normal flight planning procedure that the variable reserve is included in this fuel available at CP, i.e., if the diversion fuel to the EDTO alternate is, say 22000kg, then, included in this is the 2000kg or ‘original ‘ variable reserve.
My query and concern is this: if any or all of the variable reserve is burned in the 7 hours preceding the arrival at the CP, then you will be up to 2000kg shy of diversion fuel given the depressurisation scenario.
When I asked the question of the planning department, they said this was acceptable risk (I am aware that the whole EDTO operation is based on statistical data and risk management. I get that). What worries me is that, after engine start, I taxy to 34L in Sydney, then there is a weather delay and a runway change to 16R and before takeoff I have eaten substantially into by variable reserve (maybe even close to the 2000kg). So, before I even depart, I know that I am going to be 2000kg short of diversion fuel at the CP (and this is before the 7 hours ahead, complete with potential weather deviations, flight level unavailability, icing, etc.). Is this sensible? It seems beyond the realms of good risk management.
Does your company use the Variable Reserve as a component of your CP fuel scenario?
Am I missing something here, or is this really just a con job to reduce fuel uplift?