A330 tanking fuel to hot / humid places & top wing icing

[winglit]

I am the station engineer of a Caribbean outstation. Most of my bread and butter is A330 ETOPS work.

I have a question about tanking fuel on an A330 to hot and humid countries. Apparently the fuel where I am based is very expensive compared to the UK and recently I have noticed the aircraft landing with more and more fuel. Today for example an aircraft landed with 22,600kgs.

Even though it was 32C outside and the sun was shining we still had a build up of ice on top of the wing by the wing root and above the outer tanks. The cold soaked fuel was at -18 on arrival and the condensation on top of the wing quickly turned to ice. Even after refuelling up to 53,000kgs it was still indicating -6.

I would have thought it would have been prudent to have opened the manual transfer valves and emptied the outer tanks into the main wing tanks on arrival, to at least alleviate ice build up on the outer wing surface.

Can anyone tell me what the maximum arrival fuel load would be to ensure that no fuel is in contact with the upper skin surface of the wing?

As you can imagine we are not equipped for de-icing in the Caribbean and it's quite embarrassing telling the passengers that they have to wait for the ice to melt off the wings!

[Henry VIII]

-200

Blw 4.5 tons inner, trim tank fuel in moved toward inner.
Blw 3.5 tons inner, outer fuel is moved toward inner.

I do not have written figures, I can expect no contact on wing tips with less than 6 tons.

[A330AV8R]

and in adittion to what henry said an outer to inner tank transfer automatically happens during descent however on landing if you can also do a transfer manually if the same has not occured especially after flying for prolonged periods to avoid the above problem


ps : On a lighter note where are you ? would like to enjoy the sun and sea down there !!!

[Swedish Steve]

I have had this problem in the past. There is only one way to stop tankering, and that is to present an economic case. Yours will be to prove to the airlines that they are getting delays because of it. Delays cost big money and a few delays due tankering and it will stop.
My case was easy. They used to tanker on B734. I found out by trial and error that the max fuel on landing to avoid top wing icing was about 3500kgs. The saving into here was around 10GBP/ton, and the deicing cost was around 500GBP/occasion. They soon stopped.
All talk of the environment falls on deaf ears, only money talks.

With other aircraft you can use the centre tank. Big problem on A330 as there isn't one! On A319 I transfer fuel into the centre tank after arrival, putting about 3000kgs in the centre and leaving only 100kgs in each wing. This works well, and I have a long turnround to do it.

[BOAC]

Boeing got around this by allowing upper 'fuel frost' on the NG within defined locations and ambient conditions which avoided the need to call for the non-existent de-icing rig in Malaga in July

[lomapaseo]

The folks at Long Beach learned that you can still form ice on the top of the wing even when the fuel isn't high enough to be in contact with the top. Something to do with convection and conduction.

At least the A330 doesn't have engines behind the wing.

[NG_Kaptain]

On the 340, in my previous company, we used to transfer outer fuel manually after landing at our European and North American destinations, never had any unusual icing problems, did not tanker to the Caribbean. Flew the NG cannot remember any issues outside the ordinary. On the MD we almost lost an aircraft due to ice-nine on takeoff roll and double engine failure prior to V1, after which the policy was for engineering to transfer as much wing fuel to the centre tank after landing then top up the wing tanks using warmer fuel from the station, that seemed to work ok. At my present company occasionally find ice under the wings after ULR flights even though the OAT is 46 deg C (how do you ask to de-ice when its too hot to walk about ), normally is gone by the time fueling is completed.

[whodunnit2]

I have flown the 330/340 300 series aircraft. My company's SOP's are to manually tx the outer tanks to the inners on landing if you have more than 12,5T of fuel and the outer tank fuel temperatures were below -15 in flight.

We recently had a medical diversion into Darwin and had a wing full of ice with an OAT of 40 deg Celcius!

W2

[engineer07]

The problem with ice on the outer tank upper surface is easily solved. In fact the Outer Tk's should be empty at landing as an Outer -> Inner Xfer should be done when RTD (Remaining Time to Desitination) reaches 30 mins. If not you can empty the outers with a MAN Outer -> Inner Xfer on ground.

The problem on the inner wing is caused by fuel in the collector cell - which is kept full whatever the fuel load. Each collector holds a bit less than 1 tonne. So even when you refuel the new warmer fuel will not mix with the cold fuel in the collector cell. Switching the engine feed pumps on will help, but not solve the problem.

[fly_emu]

Originally Posted by winglit

Can anyone tell me what the maximum arrival fuel load would be to ensure that no fuel is in contact with the upper skin surface of the wing?

We have been informed that it is between 15-18T. I have only once landed with more than 15T (due hurricane), if I remember it was about 16T and we got away with it on that day.

[bvcu]

Outer tank fuel wont transfer automatically at those fuel loads , but you can manually do that from the flight deck on arrival. We do this in cold conditions if landing with them full. The two problem areas are the inboard wing root and over the main gear supports . We find on UK arrivals on a 7 hr sector at a high level that we have this problem for 5 months of the year , plus being on a 90 min turnround gives little time for warm fuel to melt the frost . On the 330-200 i have a look fwd on both sides from L/R3 doors . Theres always a lot more there than visible through cabin windows . The patch over the gear is a problem as highly visible to pax . Problem i think is that 'frost' shouldnt be a problem , but as per 'the book' and FAA regs in particular there doesnt appear to be any way out of this as its technically ice . Aware of a problem with this on a 345 in Australia last year in the summer on a short transit after high level ULR flight, melted in sun on one side but not the other, had to turn around and let the other side melt , long delay !

[Down Three Greens]

The exact figure is 8,500kg in the inner wing tank before the fuel touches the upper surface of the wing at the wing root. Data was supplied directly from Airbus upon request.

DTG

[Meikleour]

Switching on the fuel pumps, opening the crossfeed valve and carrying out a ground transfer of fuel will change the cold fuel in the collector cells.

[kijangnim]

Greetings, as somebody wrote, as th engineer on the ground to transfert fuel from outer to inner, and then tranfer it back it will do the trick (needs 15 minutes)