early or late fuel stops?

[rsiano]

I have been flying a long time but never considered the advantages of stopping early in your flight or late in the flight if a fuel stop is required. What are the advantages of stopping early versus stopping late into your flight? Are there any?
Consider the decision is to be made prior to departure from Beijing...
Lets take the example of a flight from Beijing to New York. The aircraft is not capable of making the flight non-stop. It does have the ability to fly non-stop to Anchorage. Would you stop in Petropavlovsk or Anchorage or some where else? I would appreciate it if you would state all your reasons for your choice. Please assume the airports where you would stop to have equal fuel prices, services and capabilities.
Thanks!

[Cough]

I guess we need to know whether this is the planning stage, or in flight scenario?

[rsiano]

The decision is to be made while still on the ground in Beijing...
Thanks.

[Cough]

Ok, without going into specifics of actual airports, I would go for an early one. Get out of A relatively light, and whilst transiting to B prepare for the stop. Then get on the ground with a light aircraft and get the aircraft turned with Flight Crew who aren't tired, thus less chance for error during the turn. Once enroute again, they will then get good rest on their breaks as they won't be mentally preparing for the turn. Overall safer IMHO.

However, the world doesn't work like that. The earlier stop may involve a technically more challenging destination where the risks are reversed. Thus, it should be down to the overall risk management decision by the crew.

[TopBunk]

In your given example:

GC route ZBAA-KJFK = 5930nm

GC route ZBAA-KANC-KJFK = 3400+2935nm = 6335nm

GC route ZBAA-ULPB-KJFK = 2065+4765nm = 6830nm

On that simple basis, and the fact that route via ULPB is westbound, and therefore with a statistical headwind, then eastbound must be the quickest and cheapest routing.

It then becomes one of optimising costs and crewing implications as cough alludes to.

[Dairyground]

Ignoring the specific example given, and also issues such as winds and crew tiredness, my intuition would be to stop for fuel as near to the half-way point as possible. That way you minimise the weight lifted at any point, carrying as little fuel as possible a long way before burning it.

[stilton]

Given that stopping at all is not preferred by anyone (passengers or crew) and is probably considered a great inconvenience I would suggest looking at other factors than solely technical.



Stop where you can clear customs and immigration so when you do finally arrive (probably late) passengers can exit, pick up their bags as quickly as possible and be on their way without further hassle or delay.

[AerocatS2A]

Agree with Dairyground, from a pure performance aspect, plan for a halfway stop so that fuel uplift is minimised. You can either go lighter and get better economy or you can take more payload.

[mustafagander]

Aerocat is right. As near to half way as possible minimises fuel burn if you really know that you can't make it.

OTOH if you can ALMOST carry the required fuel, make your in flight re-dispatch point as late as possible. Otherwise think about a fast plan for both sectors to preserve ETA.

If you must make a tech call NEVER let the punters off the a/c!! A "splash and dash" can be done in 40 minutes if the groundies are worth a damn.

[rsiano]

Hi,
I would like to modify my original post to consider only the total fuel burn for a trip that requires a fuel stop. If the minimum total fuel burn is the only consideration, than it appears that a fuel stop that is half way between the point of take off and the destination would be required?
What do you think?
Thanks!
Dick

[johns7022]

While there are tons of factors which help you decide where to fuel up I think I might understand what the op is asking....

I have chosen longer initial legs in the past due to the first part of the trip having favorable winds....the first and second legs were the same 'flight time' but I went much further on the first leg, so I took advantage of that......I have also opted for a very close fuel stop, when I didn't want to land in another country, but opted to fuel up just outside of it, then have enough fuel to miss it entirely and get to my destination...

I mean if your halfway point was North Korea.....you wouldn't land there just because it's half way...

I have also landed later knowing that a 5 am departure, means that many peeps will sleep most of the flight....so a longer initial leg they sleep through, then maybe time the stop for breakfast, or lunch..

Always nice to say after that stop...only a few hours to go, vs...another 4 hours to go....

[galaxy flyer]

First, I wouldn't stop in Petro, if there were any other options--don't like the runway, the terrain, the restricted exit points for the permits and don't like the weather. Other than that, a perfect stop.

All things be equal, I'd prefer for the pax to stop later than earlier; it is nicer to say, "Just two to go". As a crew member, I'd rather stop earlier because you are fresher, the limiting take-off is lighter (if an issue) and, if augmented, lots more time to arrange crew rest times.

GF