EDTO fuel - variable reserve at CP?
Well your VR is capped and planned to be there at your destination. However you can burn it enroute due to a myriad of circumstances.
In the planning stage of an etops flight, the VR is assumed to be there at the CP and then becomes fuel available, plus ETP buildup, plus other contingencies to have the required fuel at the ETOPS alternate. Just like if you refile a plan based on an ETP or PNR from an adequate the original VR becomes available flight fuel and the VR from the refile point could become next to nothing increasing your available payload from departure. Unfortunately navarus in my airline doesn't have the capability to base it on a PNR, only an ETP and therefore quote often the flight planning department caps flights as they don't want to do a manual PNR refile.
The fuel in excess at the alternate gives you an idea how much fat is in the system. It'll also say what the limiting scenario was. Depressurised, SE etc. It's a good idea to 'pump' this up a notch. You don't want to find yourself in a situation where you arrive at an alternate with 10 mins single engine reserve, a failed engine and a TCU sitting overhead......although to play Devils advocate and company man, what's the odds of this happening? You're having a pretty bad day if you find yourself there... Probably in the sim no doubt.
In the planning stage of an etops flight, the VR is assumed to be there at the CP and then becomes fuel available, plus ETP buildup, plus other contingencies to have the required fuel at the ETOPS alternate. Just like if you refile a plan based on an ETP or PNR from an adequate the original VR becomes available flight fuel and the VR from the refile point could become next to nothing increasing your available payload from departure. Unfortunately navarus in my airline doesn't have the capability to base it on a PNR, only an ETP and therefore quote often the flight planning department caps flights as they don't want to do a manual PNR refile.
The fuel in excess at the alternate gives you an idea how much fat is in the system. It'll also say what the limiting scenario was. Depressurised, SE etc. It's a good idea to 'pump' this up a notch. You don't want to find yourself in a situation where you arrive at an alternate with 10 mins single engine reserve, a failed engine and a TCU sitting overhead......although to play Devils advocate and company man, what's the odds of this happening? You're having a pretty bad day if you find yourself there... Probably in the sim no doubt.
There may be people that hate it but the fact remains that EDTO operations is a 'planning' exercise. Once you have dispatched then your 'normal' in flight fuel policy will apply. That would usually be along the lines of have enough fuel on-board at all times to proceed to a suitable (useable) airport, with a variable reserve, fixed reserve and any weather traffic holding that may need to be applied!
If you are concerned about not having enough fuel at the CP to meet the flight plan requirements then you can:
- Take more fuel
- Use a re-clearance plan
- Nominate another alternate along the way that fits within the fuel policy.
Personally when reviewing the plan, if the most critical CP has a fuel in excess of less than 20 minutes then I just take more fuel to ensure that I always have in excess of the flight plan after unforeseen senarios like a long taxi, weather etc. This is just something that I do, the company would rather that I just take flight plan fuel, but hey that is why I am paid to be in-charge, to make my own decisions that I am comfortable with.
If you are concerned about not having enough fuel at the CP to meet the flight plan requirements then you can:
- Take more fuel
- Use a re-clearance plan
- Nominate another alternate along the way that fits within the fuel policy.
Personally when reviewing the plan, if the most critical CP has a fuel in excess of less than 20 minutes then I just take more fuel to ensure that I always have in excess of the flight plan after unforeseen senarios like a long taxi, weather etc. This is just something that I do, the company would rather that I just take flight plan fuel, but hey that is why I am paid to be in-charge, to make my own decisions that I am comfortable with.
OK4Wire:
I suspect we work for the same outfit. For what it's worth, I agree with most of your comments, except for:
That is true, except that when determining if any mandatory build-up is required to satisfy the diversion fuel requirements, the AIRPATH system assumes that the contingency fuel is being used as the flight progresses towards the CP. The aircraft should therefore arrive at the CP with the diversion fuel intact even if the contingency fuel has been used up to that point. Different story, perhaps, if the contingency fuel for the entire flight has already been used.
I suspect we work for the same outfit. For what it's worth, I agree with most of your comments, except for:
My flight plan does use the variable reserve at departure as part of the fuel required, as you state.
