Trident 3 Fuel Planning

[Graeme]

Hi All,

First two flights completed successfully. Fuel predictions calculated as follows:

Taxi Out, Take Off & FL250 Climb - 2400KG
Cruise / Climb FL250+ - 4500KG / hour
Decend & Landing - 1300KG
FL250 Climb Distance - 90NM
FL250 Descend Distance - 80NM
10 min hold at 7000ft - 1000KG

So for EGLL - EGPF (Direct Routing):

Cruise GS - 500Kts
Sector Length - 300NM
Cruise Distance - 130NM
Cruise Burn - 1170KG
Normal Burn - 4870KG

15min Hold Allowance - 1500KG

Required Fuel Load - 6370KG

Have Fun!
--Graeme

[petermcleland]

Hi All,

First two flights completed successfully. Fuel predictions calculated as follows:

Taxi Out, Take Off & FL250 Climb - 2400KG
Cruise / Climb FL250+ - 4500KG / hour
Decend & Landing - 1300KG
FL250 Climb Distance - 90NM
FL250 Descend Distance - 80NM
10 min hold at 7000ft - 1000KG

So for EGLL - EGPF (Direct Routing):

Cruise GS - 500Kts
Sector Length - 300NM
Cruise Distance - 130NM
Cruise Burn - 1170KG
Normal Burn - 4870KG

15min Hold Allowance - 1500KG

Required Fuel Load - 6370KG

Hmmm...My distant memories tell me that I might have been a little unhappy with a Traffic Dispatcher offering that fuel...I just seem to remember the regulations seemed to insist on Alternate Fuel plus 45 mins holding :roll:

[Graeme]

Heh Heh

Competetive times Peter, and she has to compete with CFM56 powered Orange jets

Personally, I perfer at least 9500 KG for that route, especially if I'm doing the SID & STAR procedures.

As an aside, when flying a SID from Glasgow or LHR, the initial height on the SID is 6000FT, (ie from Glasgow cross New Galloway at 6000). Is it normal to fly the whole procedure at 6000FT and 220 Knots, or would ATC normally allow a climb before the end of the procedure?

Cheers,
--Graeme

[RAF_Quantum]

Hi Graeme,

Once the initial 'hit' has been taken by refuelling an empty aircraft, there should always be left in the aircraft the calculated diversion and holding fuel. So if you plan for example a 45 minute hold and then a 45 minute diversion and never use it, you will always have that contingency fuel left onboard and only need pay for the sector fuel each time.
Once the dust has settled and I get time to 'breathe', we'll come up with a 'policy' for pilots to work to. This will ensure that give or take a few kgs depending on aircraft type and individual flight circumstances, we can always expect a certain amount of fuel to be left in the aircraft for the next pilot. No prizes will be given for running out of fuel due to unexpected headwinds/ATC delays.

Rgds

John

[Graeme]

So if you plan for example a 45 minute hold and then a 45 minute diversion and never use it, you will always have that contingency fuel left onboard and only need pay for the sector fuel each time.

Hi John,

No problem, for the time being I'll ensure there is a reserve of 8000KG above the planned fuel. This allows 40+ minutes holding and a diversion of 250NM if diverting from the hold, or 350NM diversion from cruise.

How would one plan for the potential requirement to hold at the alternate? Would than be included in the 45 minute hold reserve? i.e. 30 min hold at the intended destination, and then 15 min hold at the alternative?

Cheers,
--Graeme

[RAF_Quantum]

Hi Graeme,

I believe a 'standard' contingency fuel is:

a. 45 minutes hold time at dest (don't forget hold should be at reduced speed to minimise size of 'racetrack' and should also mean a reduced fuel burn)

b. Diversion fuel to alternate airfield. Most shorthaul flights should have good alternative within 30 mins


I am sure some of our ex pilots here will advise if thats about right. Should be no need for double holding fuel.

Rgds

John

[PeteP]

Is it normal to fly the whole procedure at 6000FT and 220 Knots, or would ATC normally allow a climb before the end of the procedure?

In the UK, the general principle is that an aircraft will be taken off a SID (vertically and/or laterally) as soon as it's practicable to do so - in other words, as soon as there's some advantage in it for the controller! The actual moment an aircraft is taken off the SID will depend on the airport it's come from and the traffic conditions at the time.

I notice you also mention speed restrictions. Again, the usual UK practice is for the controller to cancel the 250KIAS below FL100 departure speed restriction at the earliest opportunity. I stress 'usual' because at the moment, there is a 3-month trial running where controllers have been instructed not to remove the speed limit on LTMA departures to see if this has any effect on movement rates, however, in about a month's time when the trial ends, we should be back to normal.
Pete

[Graeme]

Thanks All,

I'll update my fuel planning spreadsheet tonight. I'll recalculate my hold fuel burn as well, as it seems a bit high.

Thanks Pete, I have a feeling I'll be cleared direct to Dean Cross with no ATC speed restriction a lot more now

Cheers,
--Graeme