Long distance flights. Fuel and Pax trade off.


#1

There has been w squawk up about a Qantas flight from Sydney to Dallas (SYD-DFW) that returned to SYD for a mechanical issue. The Squawk generated much discussion.
It got me wondering if on these very long flights there has to be a trade off between pax and fuel to enable the flight to be non stop and have the required reserves. Another long flight that comes to mind is Delta and their DL200/201 from ATL to JNB. (JNB has an added complication of density altitude for the return leg.
Any information would be of interest, just for curiosity. It would be especially good to hear from pilots who have experience on these long routes.


#2

Yes, there is a trade-off between fuel and passengers, and also cargo. This is actually true on many flights, not just the ultra-long distance flights.

Aerolineas Argentinas had a flight between Buenos Aires and Auckland. The flight was operated with a 747-200. It was able to fly nonstop from Auckland to Buenos Aires. In the other direction it needed to stop in Rio Gallegos (southern Argentina). This was in 1987.

According to the June 1977 Varig/Cruzerio timetable, a flight was operated between Rio de Janeiro and Johannesburg. The flight from Rio was nonstop while the return flight was via Cape Town.

Aeromexico operates flights between Mexico City and Tokyo. While technically possible, the amount of passengers that could be carried would be reduced so the outbound flight from Mexico City stops in Monterrey. It operates nonstop to Mexico City.


#3

Interesting about that Aeromexico flight to Tokyo. Because of the high altitude of Mexico City, airplanes are quite restricted in how much they can weigh and still safely takeoff. As the previous poster pointed out, they would have to leave behind a lot of cargo and/or passengers to fly from Mexico City nonstop to Tokyo. But by flying to Monterrey, they can leave Mexico City with a lot of passengers and cargo, but not much fuel. Then they can load up with fuel at Monterrey, and take off with a much higher weight.
I see that is now a Boeing 787, when they used to use a 767 they made the stop in Tijuana, just south of San Diego.