A Challenging Endurance Problem

[misd-agin]

I'm not sure if this PROVES your question -

Boeing 777 performance manuals -

weight at start of problem - 480,000 lbs.
fuel on board 96,000 lbs (nearest 1,000)
avg weight during problem - 432,000 lbs
weight at the end of the problem - 384,000 lbs.


Best holding altitude (minimum fuel burn) -
480,000 FL290
432,000 FL310
384,000 FL310

FL310 is the answer




Speed? In the aircraft I'd adjust the ZFW to generate an a/c gross weight of 435,000 lbs and fly the FMC generated holding speed (Vref +100 minimum).

Since we don't have an FMC available I'd use -

.64/234KIAS/381KTAS (*)


480,000 would be Vref +93
432,000 would be Vref +100
384,000 would be Vref +108

* - speeds estimated from charts and not calculated