Primarily for general aviation discussion, but other aviation topics are also welcome.
Genghis the Engineer wrote:Unfortunately, you'd lose your wager.

Lots of research is out there to show that the optimal distance is around 3000nm. Below that the extra fuel on departures and climbs pushes the per-mile fuel burn up, above that the extra weight on board pushes the fuel burn up.


If the aim is to go from A to C then there is nothing gained from a stop at B.

It is not only time but also fuel inefficient as there is much more fuel wasted in landing, taxying, taking off and climbing to the high flight Levels than just staying there in the first place.

That flying non-stop is more expensive than with stops has everything to do with the fact that Airlines like the hub and spoke model to get higher passenger loads and that passengers like to fly direct and are willing to pay extra for the privilege rather than any extra fuel Costs.

The extra costs of having crew work longer and therefore more staff required etc would outweigh the fuel savings by a massive factor.

If people want to do something about green-house gasses they should fly less, not go on cruises, put PV panels on their roofs, eat less meat, and buy EVs.

Flying shorter routes is not the answer.
<Tankering drift:>

.. At Channel at ZSD (as sleepy Stansted was in the '60s :) ), two of our regular (weekly, IIRC) Comet 4B charter destinations were Varna and Constanta on the Black Sea. At both of these fuel was expensive, and had to be paid for in US$ in cash (at one, I forget which) and cash or Travellers' Cheques at the other; not the usual fuel company cards, acceptable all over 'Western' Europe. Fees (approach, landing, handling, ..) had to be paid the same way. It was a hassle going to the bank to get the cash and cheques, and for Captain to sign the blank cheques before setting off, which only he could then countersign at the destination.

Fuel was the biggest potential cost, so we always left ZSD with full tanks, which runway length there easily allowed. This was usually enough to do out and return legs with legal reserves on return. If it was not, through winds or ATC delays, then we would divert, usually into Ostend which had some of the cheapest fuel and fees in Northern Europe for some reason, on the return leg. Our accountant assured us that this tankering was cost-effective even without the reduced hassle.

GTE , was trying for a better word , brain came up with Bunker or Bunker fuel . Dictionary no good so off to Wi.....a .
Tho' PaulSS having been born in a dark blue suit might be more able .

'' The Australian Customs and the Australian Tax Office define a bunker fuel as the fuel that powers the engine of a ship or aircraft '' .
A couple of snippets..
'' No. 5 or 6 are also commonly called heavy fuel oil (HFO) or furnace fuel oil (FFO) ''.

'' HFO is still the primary fuel for cruise vessels, a tourism sector that is associated with a clean and friendly image. In stark contrast, the exhaust gas emissions - due HFO's high sulphur content - result in an ecobalance significantly worse than that for individual mobility '' .

'' Emissions from bunker fuel burning in ships contribute to air pollution levels in many port cities, especially where the emissions from industry and road traffic have been controlled. The switch of auxiliary engines from heavy fuel oil to diesel oil at berth can result in large emission reductions '' .

'' CO2 emissions from bunker fuels sold are not added to national GHG emissions '' .

Conclusion .. don't think jet fuel can be classified as Bunker fuel.
Much more science than my aged winged tractor driver brain can handle .
Agree on saving the planet , but that has to go upstairs to management and commercial department ; not to mention politicians .
We at the operating level had/have enough problems keeping safe , on track , ontime for long enough to hopefully enjoy a pension .

And of course pump out some GHG from an old O-200 on days off [ if we didn't laugh about it , we'd cry ] .

hopefully no offence given ,
rgds condor .
No offence taken at-all Condor - we're all debating politely, and as you've illustrated yourself, tankering is probably the least worst term we can all think of. Being back in the office now, I pulled an ATPL TK book off the shelf, which defines tankering as "carrying extra fuel for economic or planning reasons" - I agree, not quite what I was defining, but equally, perhaps the least worst term we can find at the moment.

I think I'd be quite happy to take that wager of my empirical evidence of a few hours on the 747-400 (flying plenty of routes > 3000nm) versus your theoretical research figures.

My single sector only takes off and climbs once......that is where the fuel is used. Your two sectors has two take-off and climbs. Yes, they will be at a lighter weight but when you look at the fuel flows there won't be a big difference.

If we were to split the one sector in half then my mid zone fuel burns would be less than the total of your two because you're carrying extra weight because you've got the minimum fuel required at destination twice. I would have it once. Even if we allowed for an alternate at exactly the same distances then you'd still be required to have alternate fuel plus reserve fuel twice and that means carrying and burning extra fuel on your first sector. Yes, my fuel burn would be higher at the same stage but later mine will be lower because of the reduced weight I'll be carrying.

There are plenty of theories out there about optimal distances etc but so many times these just don't beat scrutiny in the real world. The cost index stuff always gets me. I absolutely understand every facet of the cost index calculations but if I fly at M0.82 in a 767 I will always make more fuel and more time than if I muck around with cost indexes. Ahh, you say, that doesn't take into account people costs etc. In theory, no, it doesn't but if I use less fuel AND reduce my flight time then I save a damn sight more, especially if paying for power by the hour.

I will see if I can get our ops people to plan a route for a 787-900 from NRT to JFK direct and then in two legs and see what the fuel burn would be. I think that would be quite interesting.
Paul , are you on the Plastic Fantastic now ?

On the cost index , I believe the 'Bois and 'Gurls on the late JFK are flight planned at 400 [ max ] , to avoid having to use another terminal . 'Cos the Customs and Immig. at home terminal have gone home .
Me , I found using .86 much easier than messing with 't 'pooter .

rgds condor ,

Now using ESOPS rules for 2hr legs in the Condor .

* Extended range Single Engine Ops .
i.e. Ration fluid intake B4 flight . Otherwise it's not a gas 'n go , but offload yellow hydraulics 'n go .
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Isn't it spelt "Aesop's", or is that just a tale?

Different company now but you're absolutely right, 0.86 was definitely the way to go (until they tried to change the MIA crewing). I was meant to be on the the PF in my new bunch but they've delayed all the conversion courses until they can get RR to fix a few donks. Meanwhile we're picking up the slack on the 76 :-(
PSS , yes Aesops fables .... but Aeroplane Extended range Single Ops would work just as well ...
Hope your new 'donks are expedited .
Kanga , think MIA is when you cannot find the guy who's due to be back on duty after crew rest , or of course the original KIA ... when the skipper expired in the bunk ....
LAX .... is 'wot happens when leaving an Indian nightstop and climbing 'thro 5,000' .
Sorry , but you'll have to explain the last .

rgds condor .
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condor17 wrote:..
Sorry , but you'll have to explain the last .

rgds condor .

GLO is IATA code for Staverton, when it had scheduled services. These never included BA although it did at least one of its antecedents, Cambrian, once a BEA subsidiary.. the feeble :oops: pun was that someone who had been running might 'glow' a bit
The IoM flights to Staverton and Jersey went from Manx2 to Citywing. Latter used Let-410s, but lost its operating license in 2017 after an incident on its Manchester route. Since then no scheduled services at Staverton. Apparently the Staverton route was profitable with that size of aircraft, the Let having succeeded the Dornier of Manx2. However, there was a reported shortage in Europe of 19-seat turboprop types to charter and crews for them.

For me, Cambrian was rival 'Brand X' to British Eagle when I worked for the latter at Speke. They competed directly on Heathrow, Glasgow and possibly Cardiff routes, IIRC. However, we had 1-11s as well as Viscounts, they only Viscounts :)
Is MIA when one crew member fails to report ? :)

Actually, you don't know how close you came to being right :D Before T5 we went through a horrible time of too few ground staff etc and almost every flight being delayed. Obviously we were trying to do our best to get everyone where they wanted to be on time and so we seemed to be constantly at 0.86 on the Jumbo. Of course, this reduced the block times over the season and some Management wonderbrain thought it would be a great idea to remove the third pilot from the MIA as the 'new' block times didn't require it. We suggested this was not a good idea but Costa Coffee Man saw an opportunity to justify his existence and so it was done. It will come as no surprise that flight times suddenly increased as normal speeds were resumed, resulting in an even poorer experience for our customers. They did eventually reinstate the third pilot but left a really bad taste in the mouth for those of us who were trying to do the best to make up for the extremely lacklustre 'management' of the move to T5 (this was some two years beforehand and lasted all that time) while, at the same time, some shiny-arsed suit wearer is trying to shove something where it doesn't belong in the anatomy of the pilots in order to get his bonus.

So, yes, MIA did involve one of the pilots not reporting :D
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