After reading some stuff about the limits on twins out of JNB, I ran a calculation for a 767-300ER
(I don't have 777 numbers available)
and the results showed that a flight to Europe from JNB would almost not be possible.
As follows: FAOR-EGKK, 22degC with 9kt headwind departing runway 03L, using Flaps 15 and packs off,
I get a field limited MTOW of 154,577kg. With absolutely zero payload, it would only just make the flight.
Pretty much any payload puts it over the field limited MTOW. Fuel came in at 64,800kg. (Seems a bit high?)
How did Nationwide Airlines used to operate to Gatwick with that sort of restriction? 230 passengers would be roughly 23,000kg of payload.
Even if my fuel estimate is 10,000kg to much, that's still only half the possible passenger load.
Also, if anyone had the numbers, what would a 777-300ER's field limited MTOW be in the same conditions?