Block fuel- Help wanted
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Block fuel- Help wanted
Good morning all,
Was wondering if turbo prop/jet pilots could help with their block fuel?
As part of a university project I am undertaking research into how the pilots make sure a company offered fuel load is acceptable: What gross error checks are used?
Thanks in advance
Was wondering if turbo prop/jet pilots could help with their block fuel?
As part of a university project I am undertaking research into how the pilots make sure a company offered fuel load is acceptable: What gross error checks are used?
- Fokker F27
- DHC8 (all types)
- ATR 42 and 72
- CRJ200
- B717
- DC9 ( all types)
- A320- A321
- A330 200 and 300
- A330 NEO (800-900)
- A340 300 and 600
- A350
- B757 200 and 300
- B767 200ER and 300 ER
- B777 all series
- B787 900
Thanks in advance
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Hi Aumonier,
In 99.99%% of cases, the fuel the company (or more specifically, the Flight Operations department) gives us sufficient to perform the flight safely and arrive with above legal minimums (30 mins holding fuel). Sure we can use an average fuel flow to perform a quick gross check but these days more commonly we need to take other matters into consideration. In order to produce a BLOCK fuel figure, the route the company thinks we are going to fly needs to be accurate. It used to be that they all used to plan fuel for the 'longest' departure procedure and the 'longest' arrival procedure. Nowadays, they don't. They use what they think we will get based on weather or past patterns they have observed. If they insert a shorter route into the flight planning system (Jeppesen or LIDO are the two most popular ones), then they will get a smaller amount of BLOCK fuel. We therefore need to sometimes uplift more fuel to match what we think we will need on the day. Secondly, we need to observe the weather and bear in mind traffic at the destination. These may require us to hold, more fuel needs to be taken for this.
In 99.99%% of cases, the fuel the company (or more specifically, the Flight Operations department) gives us sufficient to perform the flight safely and arrive with above legal minimums (30 mins holding fuel). Sure we can use an average fuel flow to perform a quick gross check but these days more commonly we need to take other matters into consideration. In order to produce a BLOCK fuel figure, the route the company thinks we are going to fly needs to be accurate. It used to be that they all used to plan fuel for the 'longest' departure procedure and the 'longest' arrival procedure. Nowadays, they don't. They use what they think we will get based on weather or past patterns they have observed. If they insert a shorter route into the flight planning system (Jeppesen or LIDO are the two most popular ones), then they will get a smaller amount of BLOCK fuel. We therefore need to sometimes uplift more fuel to match what we think we will need on the day. Secondly, we need to observe the weather and bear in mind traffic at the destination. These may require us to hold, more fuel needs to be taken for this.
Only half a speed-brake
My gross error check is that I copy the OPF into the FMS and before departure, we do a triple check that the fuel displayed by the on-board SW (with full route and correct weight) matches to OFP and to what is in the tanks. It is also the manufacturer's procedure.
For the A320 as per FlightDetent.
For the Dash 8 we did our planning ourselves but it was around 1000 lbs / hour plus 200 lbs for a climb.
BAe146 is around 2000 kg / hour and 600 kg for climb.
For the Dash 8 we did our planning ourselves but it was around 1000 lbs / hour plus 200 lbs for a climb.
BAe146 is around 2000 kg / hour and 600 kg for climb.
Fuel requirements vary depending upon whether you are at the planning stage or in actual flight. Different airlines will have their own planning mothods but typically it's:
A fixed reserve - 30mins
Approach fuel - to get from 1,500' to end of the landing roll
Flight fuel - from the start of take off roll to 1,500' at destination.
Taxi fuel - from the gate to the end of the runway.
Variable reserve - 10% of the flight fuel
Holding fuel - for nominated ATC holding.
WX holding fuel - to cover any TEMPO or INTER where the weather is below the nominated holding criteria.
Diversion fuel - if the WX holding periods exceed the ability to hold.
When in flight things change and all you need is:
1) Fuel to go somewhere (anywhere)
2) 10% of (1)
3) Approach fuel
4) Minimum reserve
5) WX holding AND but not always, ATC holding
6) Alternate fuel, but only if you can't manage (5)
A fixed reserve - 30mins
Approach fuel - to get from 1,500' to end of the landing roll
Flight fuel - from the start of take off roll to 1,500' at destination.
Taxi fuel - from the gate to the end of the runway.
Variable reserve - 10% of the flight fuel
Holding fuel - for nominated ATC holding.
WX holding fuel - to cover any TEMPO or INTER where the weather is below the nominated holding criteria.
Diversion fuel - if the WX holding periods exceed the ability to hold.
When in flight things change and all you need is:
1) Fuel to go somewhere (anywhere)
2) 10% of (1)
3) Approach fuel
4) Minimum reserve
5) WX holding AND but not always, ATC holding
6) Alternate fuel, but only if you can't manage (5)
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CFM56-5A1: 0.596
IAE V2500A1: 0.581
...then, take the typical cruise thrust...
CFM: 5000 lbs
IAE: 5070 lbs
...and finally, multiply the SFCs for each engine by their typical cruise thrust to get raw ruel consumption...
CFM: 0.596 X 5000 = 2980 lbs fuel per hour
IAE: 0.581 X 5070 = 2945.67 lbs fuel per hour
Hope this helps!
A_pollo
IAE V2500A1: 0.581
...then, take the typical cruise thrust...
CFM: 5000 lbs
IAE: 5070 lbs
...and finally, multiply the SFCs for each engine by their typical cruise thrust to get raw ruel consumption...
CFM: 0.596 X 5000 = 2980 lbs fuel per hour
IAE: 0.581 X 5070 = 2945.67 lbs fuel per hour
Hope this helps!
A_pollo
Atlas, thanks, that's very interesting. Two questions, if I may:
(a) Why 1,500'? Is that height significant, or is it an arbitrary point?
(b) Why "alternate fuel, but only if you can't manage (5)"? Surely you must always provide for diversion to alternate – from anywhere, down to GA after touchdown – since many things beside WX or ATC holding can prevent you from landing at the last moment?
(a) Why 1,500'? Is that height significant, or is it an arbitrary point?
(b) Why "alternate fuel, but only if you can't manage (5)"? Surely you must always provide for diversion to alternate – from anywhere, down to GA after touchdown – since many things beside WX or ATC holding can prevent you from landing at the last moment?
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Thanks to all for the replies. I appreciate all of them!
Thanks FlightDetent, I assume the OPF is the onboard performance equipment for calculating V speeds?
I was wondering when handed the flight plan, do you check the fuel offered and check for their 'reasonableness' in what the company offered?
If it is ok, can you let me know which type you fly and what block fuel you would use?
Keep them coming folks!
Thanks to all
My gross error check is that I copy the OPF into the FMS and before departure, we do a triple check that the fuel displayed by the on-board SW (with full route and correct weight) matches to OFP and to what is in the tanks. It is also the manufacturer's procedure.
I was wondering when handed the flight plan, do you check the fuel offered and check for their 'reasonableness' in what the company offered?
If it is ok, can you let me know which type you fly and what block fuel you would use?
Keep them coming folks!
Thanks to all
Only half a speed-brake
Atlas, you need to add what type of operation and which regulatory framework the above applies to!
@OldLurker: and why no APU and de-icing fuel, why landing roll fuel, why 3 types of extra fuel...., why 10% contingency (last week I had 59 kgs on top of of 11.112 trip)
@OldLurker: and why no APU and de-icing fuel, why landing roll fuel, why 3 types of extra fuel...., why 10% contingency (last week I had 59 kgs on top of of 11.112 trip)
.
Only half a speed-brake
Then I claim the above is not typical for an airline - until a scope is attached to it. It might be common or even the rule in some place, and I am genuinely curious where that is. Not disputing a word of what is written.
I recently took a look on what the CAAC requirements are (FAA-like?) and it was a nice educative experience.
I recently took a look on what the CAAC requirements are (FAA-like?) and it was a nice educative experience.
Last edited by FlightDetent; 27th Sep 2018 at 14:44.
Your operations may well be different.
To answer three of the questions fro OL, 1500' neither significant nor arbitrary and varies from aircraft to aircraft
There is no requirement whatsoever to habitually carry an alternate. Legally, all that is needed is to have 30 minutes of fuel remaining at the end of the landing roll. It may vary slightly, but generally not very much.
In some places there might be perfectly acceptable airports within only a few miles and the alternate is almost in the circuit - Heathrow/Gatwick/Stansted for example. In such cases you can have an alternate, basically without carrying any extra fuel although these are not 'real' alternates as they are almost certain to have exactly the same weather conditions. In contrast, on a Pacific crossing for example, if you take somewhere like Tahiti, which is the only decent runway within a very long way, you cannot reasonably carry an alternate so generally there's some form of remote fuel allowance which might be something like 90 minutes of holding on top of anything else that might be required.
On arriving at destination you could have enough fuel to fly to an alternate 200 miles away, but if held for any length of time that alternate option will disappear. You may still be able to carry a closer airport, but eventually, you'll be left with only one choice. Managing when to hold and when to divert and more importantly if you'll let options disappear, is what we are supposed to to, is it not......?
It's not impossible that you might not be able to consider one place, and so another may be of interest. The option to go to somewhere may exist right to the gate or it could disappear whilst airborne. What's the weather at all of these places. What requirement do they have. There is NO fixed answer and if we play the 'what if' game, then it's easy to come up with ones that are difficult to comply with.
To answer three of the questions fro OL, 1500' neither significant nor arbitrary and varies from aircraft to aircraft
There is no requirement whatsoever to habitually carry an alternate. Legally, all that is needed is to have 30 minutes of fuel remaining at the end of the landing roll. It may vary slightly, but generally not very much.
In some places there might be perfectly acceptable airports within only a few miles and the alternate is almost in the circuit - Heathrow/Gatwick/Stansted for example. In such cases you can have an alternate, basically without carrying any extra fuel although these are not 'real' alternates as they are almost certain to have exactly the same weather conditions. In contrast, on a Pacific crossing for example, if you take somewhere like Tahiti, which is the only decent runway within a very long way, you cannot reasonably carry an alternate so generally there's some form of remote fuel allowance which might be something like 90 minutes of holding on top of anything else that might be required.
On arriving at destination you could have enough fuel to fly to an alternate 200 miles away, but if held for any length of time that alternate option will disappear. You may still be able to carry a closer airport, but eventually, you'll be left with only one choice. Managing when to hold and when to divert and more importantly if you'll let options disappear, is what we are supposed to to, is it not......?
It's not impossible that you might not be able to consider one place, and so another may be of interest. The option to go to somewhere may exist right to the gate or it could disappear whilst airborne. What's the weather at all of these places. What requirement do they have. There is NO fixed answer and if we play the 'what if' game, then it's easy to come up with ones that are difficult to comply with.
As an ex LGW pilot.
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Good technique! At the outfit where I work (Airbus Fleet) nobody knows the FUEL PLANNING function on the init-B page...
