Trans-Pac Fuel Stop?
 

Recently flew SFO-PVG. About 3/4 of way through flight Captain announced " must make fuel stop in Tokyo because of strong headwinds". Flight is normally about 12.5 hours....should have a full up capacity of at least 14.5 hours flight time. Could there have been a fuel leak, not sufficient fuel in SFO to actually get the plane all the way, or they actually budget so closely fuel ration to destination that headwind could require a fuel stop? Have not experienced this before and was told in PVG there were no earlier weather issues.

Headwinds can exceed 100 mph.

Sometimes fuel stops happen. UA and other carriers would prefer to avoid them since a fuel stop costs the airline more money than it would to operate the flight w/o one.

From what I recall headwinds may have been in the 100 mph range. Seems the headwinds should be a known factor prior to takeoff. So fuel load had the possibility of being adjusted up. Would assume that the cost to refuel would substantially outweigh the cost of topping off fuel.

Unfortunately, predicting the weather is a black art. They likely loaded enough fuel for the expected headwinds plus a buffer. Once in the air the weather may have changed a bit causing much stronger than expected winds. They may have also been put on a less than optimal flight path (after departure) that required them to fight heavier winds and burn more fuel.

Must have been consistent strong winds as the return flight a few days later rocketed across the pacific in just 9 hrs. 9 hrs is like a day in the park compared to 15.5 on the way over!

You'd be surprised. After all, to carry extra fuel means to carry extra weight, which requires more fuel, which makes the plane heavier which...I've gone crosseyed.

Fuel planning has always been fascinating to me. For an international flight like that, the fuel required would include enough to:

-Fly to and land at the airport you're relased to
-After that, fly for 10% of the total time required from the airport of depature and the airport to which you are released
-Thereafter, fly to and land at the most distant alternate
-Therafter, fly for 30 minutes at 1500 ft. above the alternate airport
-Any additional fuel required to meet ETP requirements (Equal Time Points - The point where you would choose to push on or turn around if there was a problem in flight)

The above was paraphrased from Doug Snow's excellent PS1FPLAN manual.

Also, if there were 100 knot headwinds, you are essentially adding 100 miles to your trip journey for every hour you fly, and over 12 hours, that can add up!

Regardless, better to stop and refuel than the alternative. :)

Fuel stops are quite normal, and this is no reason to think that the captain was covering up ........anyone making runs to SYD can verify this.

Sometimes it is known before take-off, sometimes not. There are choices to be made and this is better than leaving 1 passengers behind in order to make flight completion.

In some cases, to minimize the fuel load, airlines will gamble on an "in-flight redispatch" on long flights. For example, they could file a flight plan for SFO-NRT and load more than enough fuel for that route, including all the contingencies mentioned by Spiff, but less than would be required for SFO-PVG. If everything goes well, they will re-evaluate the fuel situation and amend the flight plan to continue to PVG as they approach Japan. Most of the time they win at this game, but sometimes they don't have enough fuel to legally continue and have to land at the originally filed destination.

Considering that UA is not SAC. I calculated based on my "back of bus" fare of over 1200,the full load generated in excess of 1/2 million dollars. For this consideration is the fuel stop generated by economics or regulations?

Does UA have spare NRT slots to use for this? Certainly in a fuel emergency slots are out of the picture, but if UA is filing to NRT for flights actually going elsewhere wouldn't that require a slot?

Is NRT restricted by takeoff/landing slots or gate slots? A refueling stop has no need to use a gate.

Not fun, but consider the alternatives!!

This happened to me as well going SFO-PVG a few months back.

We stopped in a small Korean island off the coast. The "airport" looked like a bus stop, lots of barb wire and security on the perimeter, no sign of any commercial activity, certainly not of the size of a 747.

We remained on board, off the runway, trucks came, delivered fuel, and we took off again. Total time on the ground, my guess, ~30 minutes.

Is fuel cheaper in Asia than in the US??

Fuel might be cheaper, but landing fees and the huge amount of fuel it would take to get the big bird off the ground would certainly outweigh any savings. Maybe there's a gas war among airports. Would have to have some pretty big signs to get the airliner's attention.

:D

Just a historical FYI:

Back when United first started flying "Royal Pacific Service" from SEA to several cities in Asia using DC10s and later some old ex-PanAm 747-100s and SP's...a fuel stop in Okinawa was pretty much to be expected on most "non-stops" to many cities that lied beyond Japan. Sometimes you made it all the way with whatever they had loaded, but most of the times you did not.

Pax were never allowed off the plane in Okinawa. You just pulled up to a spot out on the tarmac, they rolled some stairs up to the plane, refueled, the pilot signed the charge slip, and you were on your way again. The whole business added about an hour to your arrival time.