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Old 1st Mar 2008, 17:53   #1 (permalink)
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Join Date: Mar 2008
Location: Atlanta, GA, USA
Age: 58
Posts: 2
Block Fuel, Taxi Fuel, Trip Fuel, and Ballast Fuel

We have a system that accepts block fuel, trip fuel (TIF), and taxi fuel. The system calculates the takeoff fuel (TOF). The system also accepts ballast fuel (weight and arm). The system defines "block fuel" to include "ballast fuel".

The system calculates TOF as follows:
TOF = block fuel - taxi fuel - ballast fuel

Ballast fuel is included with the DOW as an operational adjustement.

A question has come up regarding if the ballast fuel weight should be included in the block fuel weight. The suggestion is that block fuel should NOT include the ballast fuel and that the system should create a new field on the fuel screen called "Total Fuel" that is calculated as follow :

total fuel = block fuel + ballast fuel

Question: Is it incorrect to include ballast fuel weight in the block fuel weight?
How does your company handle ballast fuel?

Since companies seem to enter fuel figures differently, I would appreciate several responses.

Much thanks!


Last edited by pbaker01; 2nd Mar 2008 at 01:11.
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Old 1st Mar 2008, 18:49   #2 (permalink)

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My understanding is that Block Fuel should include all usuable fuel onboard an aircraft before engine start. Therefore ballast fuel should be included in this figure, even if not planned to be used.

To avoid duplicating the weight, no adjustments should be made to the DOW. The only fuel i'm aware of that is included in the DOW is unusable fuel, and this is generally included in the Basic Weight of the aircraft anyway.
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Old 2nd Mar 2008, 00:25   #3 (permalink)
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My understanding is that Block Fuel should include all usuable fuel onboard an aircraft before engine start. Therefore ballast fuel should be included in this figure, even if not planned to be used.
And the confusion continues. It could be argued, as this site does, that ballast fuel is "non-usable" fuel. Note that the definition of block fuel is the "total fuel on board".

Does anyone else have an opinion on this?

Terms from: http://www.hilmerby.com/fom/proc_speed.html

Fuel terms.

Ballast fuel. Non-usable fuel used for balancing purpose (only possible on some aircraft). The ballast fuel is separated from takeoff fuel (usable fuel) and loaded ia a separate tank. the fuel must not be consumed or jettisoned during flight.

Block fuel. Weight of total amount of fuel on board before starting taxi.

Burn-off fuel. Taxi fuel plus trip fuel.

Reserve fuel. Difference between takeoff fuel and trip fuel, consiting of:
  • Route reserve,
  • diversion,
  • holding, and
  • additional fuel.
Taxi fuel. Weight of fuel to cover APU consumption, engine start and ground maneuvers until start of takeoff. Standard weights are used which are, with a few exceptions, applicable at every airport.

TOF = TakeOff Fuel. Weight of total usable fuel onboard at the moment of takeoff (brake release).

Trip fuel. Weight of the precalculated fuel consumption from takeoff to touchdown at the next point of landing.
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Old 2nd Mar 2008, 10:55   #4 (permalink)
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My first post on PPRuNe and speaking from memory as it's many years since my load planning days !

I'd suggest the definition of "ballast fuel" quoted is misleading.

Ballast fuel can potentially be used on any aircraft and seperate tanks are not a requirement.

It can be quite common (or was) to use fuel as ballast on some passenger a/c which were tricky to trim on positioning flights.

The old BAC 1-11 was a good example of this ....

The ballast fuel could be used to get the weights up to keep within the positioning trim limits (and avoid loading actual ballast).

The physical location of the fuel was the same as the "normal" fuel.

The key thing is that the loadsheet clearly identifies the fuel that is carried as ballast and as such makes clear it is not available as "contingency" etc en-route.

To my mind the system described in the first post is handling this correctly..... the ballast fuel is indeed part of the FOB ..... however, it's not "usable" and so is deducted from the t/o fuel .....

As it's being used as ballast you very much need it to be part of the DOW calculations as that's where it's having it's ballast effect.

Edited to add: I concurr with DB's view .... ballast fuel is technically usable (it's in the tanks and can flow to the engines) ..... whether you'd want to might depend on the circumstances !!
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Old 2nd Mar 2008, 11:20   #5 (permalink)
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on the embraer 135/145 we usually use 600kg ballast fuel on positioners only. were not allowed to use ballast fuel to trim the aircraft on pax flights. its shown as a service weight adjustment (+600/+1.0/bal fuel) and is not included in the final fuel figures.

ie captain wants 2400kg inc ballast fuel so 2400 - 600 - 100 (taxi) = 1700kg take off fuel shown on loadsheet.
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Old 2nd Mar 2008, 12:26   #6 (permalink)
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Although ballast fuel is part of the fuel load of the aircraft it is being carried for a specific purpose, that being to avoid the need to load ballast bags or blocks. Although it could be used in an emergency situation it would be at the risk of compromising the trim of the aircraft.
For loadsheet purposes it should be shown as a service weight adjustment( or whatever term your company uses) as part of the dry operating weight calculation and so form part of the zero fuel weight. The fuel entry for loadsheet purposes is fuel on board - ballast fuel - taxi fuel.
This, I was taught, is the correct procedure and the one I have used for many a long year. In fact back to the days of the BOAC Super VC10.
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Old 6th Jan 2012, 03:32   #7 (permalink)
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Loadsheet terms

Ok, the system you're referring to is most likely the old style (originally British Airways/BOAC) ALP DCS.
This was used by most of the world's airlines and is still used by quite a few that haven't moved to the NewGen systems such as QF, BA and CX that were jointly developed by QF and BA (mostly QF) with Amadeus.
TIF and TOF, etc. represent the manner in which this information is entered into the system.
The entry code is FP - e.g.:
STF is standard taxi fuel, usually in basic records for the carrier, ETBO I just threw in there because it's not used very often but represents extra taxi burn off when additional taxi fuel is to be used. Some airlines add to the STF but the correct way is ETBO.
Now, ballast fuel is NEVER to be used.
The correct way to represent it in an automated loadsheet or a manual loadsheet, is as a Service Weight Adjustment.
i.e. it does not appear as fuel in any way. The Service Weight Adjustment represents a weight (in this case added) and an index adjustment, usually obtained from a table contained in the appropriate company manual, specific to the aircraft in question. It is usually shown at the bottom of an automated loadsheet as 'SW/ADJ' and most Load Controllers would enter it as 'Unusuable Fuel' or 'Ballast Fuel'.
We did something similar to this on long B747-400 sectors such as SYD-LAX (QF, NZ, et al) when there was thought to a be a scoring problem with fuel pumps in the HST (horizontal stabiliser tank), inspiring an Airworthiness Directive that the pumps should remain submerged at all times, therefore, a Service Weight Adjustment was done for 'Unusable Fuel' for, I think it was, 600kg in the Horizontal Stabilizer Tank. Some carriers have codes set up that indicated the location and therefore require only a quantity with a table in the basic records of the system including the Index Adjustment for a particular location - an example might be: 'XD3' for example, meaning 'Door 3' (left or right).
Hope this clarifies.
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Old 7th Jan 2012, 15:44   #8 (permalink)
Join Date: Jan 2012
Location: Brazil
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Ballast fuel

Hello Paul.

My name is Luiz, I'm a brazilian Flight Dispatcher. Just complementing your question, at the Airline I work, we used to dispatch our B727-200F using ballast fuel procedures, when there is no weight (no pallets) on board. This value of "ballast fuel" is computed as cargo, it does not considered to be used during the flight. It appears on the output format of the flight planning (at block fuel) but this value is added to ZFW as cargo. As I have said, we using to dispatch our B727-200F with ballast fuel, only when we don't have any weight on board, nor on maideck nor in the holds.
I don't know if you understood what I meant.
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